Thursday, 28 February 2013

Wyoming Toad

The Wyoming toad or Baxter's toad (Bufo baxteri or Anaxyrus baxteri) is an extremely rare amphibian that exists only in captivity and within Mortenson Lake National Wildlife Refuge in the U.S. state of Wyoming. The Wyoming toad was listed as an endangered species in 1984, and listed as extinct in the wild since 1991. Before the sharp declines occurred, this toad was classified as a subspecies of the Canadian toad.

 

 

 

 

 

Habitat

 

The Wyoming toad frequents floodplains and the short grass edges of ponds, creeks, and lakes. They frequently use abandoned pocket gopher and ground squirrel burrows as hibernacula.

Conservation history

 


Wyoming toad being examined by FWS employee
 
Relatively common in the 1950s, the Wyoming toad experienced a sharp decline during the 1970s leading to an endangered species listing and it was believed the toad was extinct by 1980. The Wyoming toad was later rediscovered in the wild in 1987 along the shores of Mortenson Lake, which is an alpine lake situated at 7,256 feet (2,212 m) above sea level. The toad is historically found only in the Laramie Basin within 30 miles (48 km) of Laramie, Wyoming. By the early 1990s a captive breeding program was begun trying to save the endangered toad from extinction, but no known wild reproduction has occurred since 1991.
Future conservation of the Wyoming toad in the wild is heavily dependent on eradicating chytrid fungus (Batrachochytrium dendrobatidis), which is probably the biggest threat to the species' survival.

Thursday, 6 September 2012

Haast's Eagle

Haast's Eagle (Harpagornis moorei) was a species of massive eagle that once lived on the South Island of New Zealand. The species was the largest eagle known to have existed. Its prey consisted mainly of gigantic flightless birds that were unable to defend themselves from the striking force and speed of these eagles, which at times reached 80 km/h (50 mph). The Eagle's massive size may have been an evolutionary response to the size of its prey, as both would have been much smaller when they first came to the island, and would have grown larger over time due to lack of competition. The Haast's Eagle became extinct around the year 1400, when its major food sources, the moa, were hunted to extinction by Maori living on the island and much of its dense-forest habitat was cleared.


Classification

 

Comparative morphology of Haast's Eagle with its closest living relative, the Little Eagle
 
DNA analysis has shown that this raptor is related most closely to the much smaller Little Eagle as well as the Booted Eagle (both of these two species were recently reclassified as belonging to the genus Aquila ) and not, as previously thought, to the large Wedge-tailed Eagle. Thus, Harpagornis moorei may be reclassified as Aquila moorei, pending confirmation. H. moorei may have diverged from these smaller eagles as recently as 700,000 to 1.8 million years ago. Its increase in weight by ten to fifteen times over that period is the greatest and quickest evolutionary increase in weight of any known vertebrate. This was made possible in part by the presence of large prey and the absence of competition from other large predators.

Etymology

 

Haast's Eagle was first classified by Julius von Haast in the 1870s, who named it Harpagornis moorei after George Henry Moore, the owner of the Glenmark Estate where bones of the bird had been found.
The genus name is a compound crassis word of the Greek word "harpax", meaning 'grappling hook', and the Greek "ornis", meaning 'bird'.

Size and habits

 
Haast's Eagles were the largest known true raptors, slightly larger even than the largest living vultures. Female eagles are significantly larger than males. Females of the Haast species are believed to have weighed 10–15 kg (22–33 lb) and males 9–12 kg (20–26 lb). They had a relatively short wingspan, measuring roughly 2.6–3 m (8 ft 6 in–9 ft 10 in). This wingspan is similar to that of some extant eagles (the wingspan now reported in large specimens of Golden Eagles and Steller's Sea Eagles). Even the largest extant eagles, however, are about forty percent smaller in body size than the size of Haast's Eagles.
Short wings may have aided Haast's Eagles when hunting in the dense scrubland and forests of New Zealand. Haast's Eagle sometimes is portrayed incorrectly as having evolved toward flightlessness, but this is not so; rather it represents a departure from the mode of its ancestors' soaring flight, toward higher wing loading. Two of the largest extant eagles, the Harpy Eagle and the Philippine Eagle, also have similarly reduced relative wing-length in adaptation to forest-dwelling.
The strong legs and massive flight muscles of these eagles would have enabled the birds to take off with a jumping start from the ground, despite their great weight. The tail was almost certainly long, up to 50 cm (20 inches) in female specimens, and very broad. This characteristic would compensate for the reduction in wing area by providing additional lift. Total length is estimated to have been up to 1.4 m (4 ft 7 in) in females, with a standing height of approximately 90 cm (2 ft 11 in) tall or perhaps slightly greater.
Haast's Eagles preyed on large, flightless bird species, including the moa, which was up to fifteen times the weight of the eagle. It is estimated to have attacked at speeds up to 80 km/h (50 mph), often seizing its prey's pelvis with the talons of one foot and killing with a blow to the head or neck with the other. Its size and weight indicate a bodily striking force equivalent to a cinder block falling from the top of an eight-story building. Its large beak also could be used to rip into the internal organs of its prey and death then would have been caused by blood loss. In the absence of other large predators or scavengers, a Haast's Eagle easily could have monopolised a single large kill over a number of days.

Maori legendry

 

It is believed that these birds are described in many legends of the Māori, under the names Pouakai, Hokioi, or Hakawai. However, it has been ascertained that the "Hakawai" and "Hokioi" legends refer to the Coenocorypha snipe – in particular the extinct South Island subspecies. According to an account given to Sir George Grey, an early governor of New Zealand, Hokioi were huge black-and-white predators with a red crest and yellow-green tinged wingtips. In some Māori legends, Pouakai kill humans, which scientists believe could have been possible if the name relates to the eagle, given the massive size and strength of the bird.

Extinction


Early human settlers in New Zealand (the Māori arrived around the year 1280) preyed heavily on large flightless birds, including all moa species, eventually hunting them to extinction. The loss of its natural prey caused the Haast's Eagle to become extinct as well around the year 1400, when the last of its natural food sources were depleted.
A noted explorer, Charles Edward Douglas, claims in his journals that he had an encounter with two raptors of immense size in Landsborough River valley (probably during the 1870s), and that he shot and ate them. These birds might have been a last remnant of the species, but some might argue that there had not been suitable prey for a population of Haast's Eagle to maintain itself for about five hundred years before that date, and 19th century Māori lore was adamant that the pouakai was a bird not seen in living memory. Still, Douglas' observations on wildlife generally are trustworthy; a more probable explanation, given that the alleged three-metre wingspan described by Douglas is likely to have been a rough estimate, is that the birds were Eyles' Harriers. This was the largest known harrier (the size of a small eagle) — and a generalist predator — and although it also is assumed to have become extinct in prehistoric times, its dietary habits alone make it a more likely candidate for late survival.
Until recent human colonisation that introduced rodents and cats, the only mammals found on the islands of New Zealand were three species of bat, one of which recently has become extinct. Free from terrestrial mammalian competition and predatory threat, birds occupied or dominated all major niches in the New Zealand animal ecology because there were no threats to their eggs and chicks by small terrestrial animals. Moa were grazers, functionally similar to deer or cattle in other habitats, and Haast's Eagles were the hunters who filled the same niche as top-niche mammalian predators, such as tigers or lions.

In art

 

Artwork depicting Haast's Eagle now may be viewed at OceanaGold's Heritage & Art Park at Macraes, Otago, New Zealand. The sculpture, weighing approximately 750 kg (1,700 lb; 118 st), standing 7.5 metres (25 ft) tall, and depicted with a wingspan of 11.5 metres (38 ft) is constructed from stainless steel tube and sheet and was designed and constructed by Mark Hill, a sculptor from Arrowtown, New Zealand.

Sunday, 2 September 2012

Yak

The yak (Bos grunniens for the domesticated, Bos mutus for the wild animal ) is a long-haired bovine found throughout the Himalayan region of south Central Asia, the Tibetan Plateau and as far north as Mongolia and Russia. In addition to a large domestic population, there is a small, vulnerable wild yak population. In the 1990s, a concerted effort was undertaken to help save the wild yak population.

 

 

 

 

 

 

 

 

Etymology

 

The English word "yak" derives from the Tibetan (Tibetan:  Wylie: g.yag), or gyag – in Tibetan this refers only to the male of the species, the female being called a dri or nak. In English, as in most other languages which have borrowed the word, "yak" is usually used for both sexes.

Taxonomy

 

Yaks belong to the genus Bos, and are therefore related to cattle (Bos primigenius taurus, Bos primigenius indicus). Mitochondrial DNA analyses to determine the evolutionary history of yaks have been somewhat ambiguous.
The yak may have diverged from cattle at any point between one and five million years ago, and there is some suggestion that it may be more closely related to bison than to the other members of its designated genus. Apparent close fossil relatives of the yak, such as Bos baikalensis, have been found in eastern Russia, suggesting a possible route by which yak-like ancestors of the modern American bison could have entered the Americas.

The species was originally designated as Bos grunniens ("grunting ox") by Linnaeus in 1766, but this name is now generally only considered to refer to the domesticated form of the animal, with Bos mutus ("mute ox") being the preferred name for the wild species. Although some authors still consider the wild yak to be a subspecies, Bos grunniens mutus, the ICZN made an official ruling in 2003 permitting the use of the name Bos mutus for wild yaks, and this is now the more common usage.
Except where the wild yak is considered as a subspecies of Bos grunniens, there are no recognised subspecies of yak.

Physical characteristics

 

Domestic yak at Yumdrok Yumtso Lake

Wild yaks are among the largest bovids and are second only to the gaur in shoulder height. Wild yak adults stand about 1.6 to 2.2 m (5.2 to 7.2 ft) tall at the shoulder and weigh 305–1,000 kg (670–2,200 lb). The head and body length is 2.5 to 3.3 m (8.2 to 11 ft), not counting the tail of 60 to 100 cm (24 to 39 in). The females are about one-third the weight and are about 30% smaller in their linear dimensions when compared to bull wild yaks. Domesticated yaks are much smaller, males weighing 350 to 580 kg (770 to 1,300 lb) and females 225 to 255 kg (500 to 560 lb).
Yaks are heavily built animals with a bulky frame, sturdy legs, and rounded cloven hooves. They are the only wild bovids of this size with extremely dense, long fur that hangs down lower than the belly. Wild yaks are generally dark, blackish to brown, in pelage coloration. However, domestic yaks can be quite variable in color, often having patches of rusty brown and cream. They have small ears and a wide forehead, with smooth horns that are generally dark in colour. In males, the horns sweep out from the sides of the head, and then curve forward; they typically range from 48 to 99 cm (19 to 39 in) in length. The horns of females are smaller, only 27 to 64 cm (11 to 25 in) in length, and have a more upright shape. Both sexes have a short neck with a pronounced hump over the shoulders, although this is larger and more visible in males. Yaks are highly friendly in nature and can easily be trained. There has been very little documented aggression from yaks towards human beings, although mothers can be extremely protective of their young and will bluff charge if they feel threatened.
Both sexes have long shaggy hair with a dense woolly undercoat over the chest, flanks, and thighs to insulate them from the cold. Especially in males, this may form a long "skirt" that can reach the ground. The tail is long and horselike rather than tufted like the tails of cattle or bison. Wild yaks typically have black or dark brown hair over most of the body, with a greyish muzzle, although some wild golden-brown individuals have been reported. Domesticated yaks have a wider range of coat colours, with some individuals being white, grey, brown, roan or piebald. The udder in females and the scrotum in males are small and hairy, as protection against the cold. Females have four teats.
To the casual observer, yaks are easily confused with Highland cattle, but upon closer examination, the physical differences are quite apparent. However, Highland cattle are shaggy, rather than long-haired, and have straight backs and tufted tails.

Physiology

 

Yak physiology is well adapted to high altitudes, having larger lungs and heart than cattle found at lower altitudes, as well as greater capacity for transporting oxygen through their blood due to the persistence of foetal haemoglobin throughout life. Conversely, yaks do not thrive at lower altitudes, and begin to suffer from heat exhaustion above about 15 °C (59 °F). Further adaptations to the cold include a thick layer of subcutaneous fat, and an almost complete lack of functional sweat glands.
Compared with domestic cattle, the rumen of yaks is unusually large, relative to the omasum. This likely allows them to consume greater quantities of low-quality food at a time, and to ferment it longer so as to extract more nutrients. Yak consume the equivalent of 1% of their body weight daily while cattle require 3% to maintain condition. 

Odor

 

Contrary to popular belief, yak and their manure have little to no detectable odor when maintained appropriately in pastures or paddocks with adequate access to forage and water. Yak wool is naturally odor resistant.

Reproduction and life history

 

Yaks mate in the summer, typically between July and September, depending on the local environment. For the remainder of the year, many males wander in small bachelor groups away from the large herds, but, as the rut approaches, they become aggressive and regularly fight amongst each other to establish dominance. In addition to non-violent threat displays, bellowing, and scraping the ground with their horns, male yaks also compete more directly, repeatedly charging at each other with heads lowered or sparring with their horns. Like bison, but unlike cattle, males wallow in dry soil during the rut, often while scent-marking with urine or dung. Females enter oestrus up to four times a year, and females are receptive only for a few hours in each cycle.
Gestation lasts between 257 and 270 days, so that the young are born between May and June, and results in the birth of a single calf. The female finds a secluded spot to give birth, but the calf is able to walk within about ten minutes of birth, and the pair soon rejoin the herd. Females of both the wild and domestic forms typically give birth only once every other year, although more frequent births are possible if the food supply is good.
Calves are weaned at one year and become independent shortly thereafter. Wild calves are initially brown in colour, and only later develop the darker adult hair. Females generally give birth for the first time at three or four years of age, and reach their peak reproductive fitness at around six years. Yaks may live for more than twenty years in domestication or captivity, although it is likely that this may be somewhat shorter in the wild.

Wild yaks

 

A herd of domestic yaks wandering in The Himalayas
 
Wild yaks (Bos grunniens mutus or Bos mutus, Tibetan:  Wylie: 'brong) usually form herds of between ten and thirty animals. They are insulated by dense, close, matted under-hair as well as their shaggy outer hair. Yaks secrete a special sticky substance in their sweat which helps keep their under-hair matted and acts as extra insulation. This secretion is used in traditional Nepalese medicine. Many wild yaks are killed for food by hunters in China; they are now a vulnerable species.
The diet of wild yaks consists largely of grasses and sedges, such as Carex, Stipa, and Kobresia. They also eat a smaller amount of herbs, winterfat shrubs, and mosses, and have even been reported to eat lichen. Historically, the main natural predator of the wild yak has been the Tibetan wolf, but brown bears and snow leopards have also been reported as predators in some areas, likely of young or infirm wild yaks.
Thubten Jigme Norbu, the elder brother of Tenzin Gyatso, the 14th Dalai Lama, reported on his journey from Kumbum in Amdo to Lhasa in 1950:
Before long I was to see the vast herds of drongs with my own eyes. The sight of those beautiful and powerful beasts who from time immemorial have made their home on Tibet's high and barren plateaux never ceased to fascinate me. Somehow these shy creatures manage to sustain themselves on the stunted grass roots which is all that nature provides in those parts. And what a wonderful sight it is to see a great herd of them plunging head down in a wild gallop across the steppes. The earth shakes under their heels and a vast cloud of dust marks their passage. At nights they will protect themselves from the cold by huddling up together, with the calves in the centre. They will stand like this in a snow-storm, pressed so close together that the condensation from their breath rises into the air like a column of steam. The nomads have occasionally tried to bring up young drongs as domestic animals, but they have never entirely succeeded. Somehow once they live together with human beings they seem to lose their astonishing strength and powers of endurance; and they are no use at all as pack animals, because their backs immediately get sore. Their immemorial relationship with humans has therefore remained that of game and hunter, for their flesh is very tasty.
—Thubten Norbu, Tibet is My Country

Distribution and habitat

 

Wild yaks are found primarily in northern Tibet and western Qinghai, with some populations extending into the southernmost parts of Xinjiang, and into Ladakh in India. Small, isolated populations of wild yak are also found farther afield, primarily in western Tibet and eastern Qinghai. In historic times, wild yaks were also found in Nepal and Bhutan, but they are now considered extinct in both countries, except as domesticated animals.
The primary habitat of wild yaks consists of treeless uplands between 3,000 and 5,500 m (9,800 and 18,000 ft), dominated by mountains and plateaus. They are most commonly found in alpine meadows with a relatively thick carpet of grasses and sedges, rather than the more barren steppe country.

Behaviour

 

Yaks are herd animals. Herds can contain several hundred individuals, although many are much smaller. The herds consist primarily of females and their young, with a smaller number of adult males. The remaining males are either solitary, or found in much smaller groups, averaging around six individuals. Although they can become aggressive when defending young, or during the rut, wild yaks generally avoid humans, and may rapidly flee for great distances if any approach.

Domesticated yaks


Domesticated yaks have been kept for thousands of years, primarily for their milk, fibre and meat, and as beasts of burden. Their dried dung is an important fuel, used all over Tibet, and is often the only fuel available on the high treeless Tibetan plateau. Yaks transport goods across mountain passes for local farmers and traders as well as for climbing and trekking expeditions. "Only one thing makes it hard to use yaks for long journeys in barren regions. They will not eat grain, which could be carried on the journey. They will starve unless they can be brought to a place where there is grass." They also are used to draw ploughs. Yak milk is often processed to a cheese called chhurpi in Tibetan and Nepali languages, and byaslag in Mongolia. Butter made of Yaks' milk is an ingredient of the butter tea that Tibetans consume in large quantities, and is also used in lamps and made into butter sculptures used in religious festivities. Yaks grunt, and unlike cattle are not known to produce the characteristic bovine lowing sound.

Yak sports

 

In parts of Tibet and Karakorum yak racing is a form of entertainment at traditional festivals and is considered an important part of their culture. More recently, sports involving domesticated yaks, such as yak skiing, or yak polo, are being marketed as tourist attractions in Central Asian countries, including Gilgit–Baltistan, Pakistan.

Hybrid yak

 

In Nepal, Tibet and Mongolia, domestic cattle are crossbred with yaks. This gives rise to the infertile male dzo as well as fertile females known as dzomo or zhom, which may be crossed again with cattle. The "Dwarf Lulu" breed, "the only Bos primigenius taurus type of cattle in Nepal" has been tested for DNA markers and found to be a mixture of both taurine and zebu types of cattle (B. p. taurus and B. p. indicus) with yak. According to the International Veterinary Information Service, the low productivity of second generation cattle-yak crosses makes them suitable only as meat animals.
Crosses between yaks and domestic cattle (Bos primigenius taurus) have been recorded in Chinese literature for at least 2,000 years. Successful crosses have also been recorded between yak and American bison, gaur, and banteng, generally with similar results to those produced with domestic cattle.

Saturday, 1 September 2012

African Elephant

African elephants are the elephants of the genus Loxodonta (Greek for 'oblique-sided tooth'), consisting of two extant species, the African bush elephant and the smaller African forest elephant. Loxodonta is one of the two existing genera in the family Elephantidae. Although it is commonly believed that the genus was named by Georges Cuvier in 1825, Cuvier spelled it Loxodonte. An anonymous author romanized the spelling to Loxodonta and the International Code of Zoological Nomenclature (ICZN) recognizes this as the proper authority.
Fossil members of Loxodonta have only been found in Africa, where they developed in the middle Pliocene.

 

 

 

 

 

 

 

Description

 

The African elephant is the largest living terrestrial animal. Its thickset body rests on stocky legs and it has a concave back. Its large ears enable heat loss. Its upper lip and nose forms a trunk. The trunk acts as a fifth limb, a sound amplifier and an important method of touch. The African elephant's trunk ends in two opposing lips, whereas the Asian elephant trunk ends in a single lip. African bush elephants are bigger than Asian elephants. Males stand 3.2–4.0 m (10–13 ft) tall at the shoulder and weigh 4,700–6,048 kg (10,000–13,330 lb), while females stand 2.2–2.6 m (7.2–8.5 ft) tall and weigh 2,160–3,232 kg (4,800–7,130 lb).[6]
The largest individual recorded stood four metres to the shoulders and weighed ten tonnes.

Teeth

Female African forest elephant with juvenile in the Republic of the Congo

Elephants have four molars; each weighs about 5 kg (11 lb) and measures about 30 cm (12 in) long. As the front pair wears down and drops out in pieces, the back pair shifts forward, and two new molars emerge in the back of the mouth. Elephants replace their teeth six times. At about 40 to 60 years of age, the elephant no longer has teeth and will likely die of starvation, a common cause of death.
Their tusks are firm teeth; the second set of incisors become the tusks. They are used for digging for roots and stripping the bark off trees for food, for fighting each other during mating season, and for defending themselves against predators. The tusks weigh from 23–45 kg (51–99 lb) and can be from 1.5–2.4 m (5–8 ft) long. Unlike Asian elephants, both male and female African elephants have tusks. They are curved forward and continue to grow throughout the elephant's lifetime. The enamel plates of the molars are fewer in number than in Asian elephants.

Distribution and habitat

 

African bush elephant
 
The African elephant can be found in Eastern, Southern and West Africa, either in dense forests, mopane and miombo woodlands, Sahelian scrub or deserts.

Classification

 

  • African bush elephant, Loxodonta africana
    • North African elephant, Loxodonta africana pharaoensis (extinct). Presumed subspecies north of the Sahara from the Atlas to Ethiopia.
  • African forest elephant, Loxodonta cyclotis
  • Loxodonta atlantica (fossil). Presumed ancestor of the modern African elephants
  • Loxodonta exoptata (fossil). Presumed ancestor of L. atlantica
  •  Loxodonta adaurora (fossil). May belong in Mammuthus.
Bush and forest elephants were formerly considered subspecies of the same species Loxodonta africana. As described in the entry for the forest elephant in the third edition of Mammal Species of the World (MSW3), there is now morphological and genetic evidence they should be considered as separate species.

Females (here bush elephants in Tanzania) usually live in smaller or larger herds

Much of the evidence cited in MSW3 is morphological. The African forest elephant has a longer and narrower mandible, rounder ears, a different number of toenails, straighter and downward tusks, and considerably smaller size. With regard to the number of toenails: the African bush elephant normally has four toenails on the front foot and three on the hind feet, the African forest elephant normally has five toenails on the front foot and four on the hind foot (like the Asian elephant), but hybrids between the two species commonly occur.
MSW3 lists the two forms as full species and does not list any subspecies in its entry for Loxodonta africana. However, this approach is not taken by the United Nations Environment Programme's World Conservation Monitoring Centre nor by the International Union for Conservation of Nature (IUCN), both of which list L. cyclotis as a synonym (not even a subspecies) of L.africana.
A consequence of the IUCN taking this view is that the IUCN Red List makes no independent assessment of the conservation status of the two forms of African elephant. It merely assesses the two forms taken together as a unit as vulnerable.
A study of nuclear DNA sequences published in 2010 indicated that the divergence date between forest and savanna elephants is 2.6–5.6 million years ago, which is virtually the same as the divergence date estimated between the Asian elephant and woolly mammoths (2.5–5.4 million years ago), strongly supporting their status as separate species. Forest elephants were found to have a high degree of genetic diversity, perhaps reflecting periodic fragmentation of their habitat during the climatic changes of the Pleistocene.

Behavior

 

African elephant society is arranged around family units. In each family unit are around ten individuals made up of closely related females and their calves. Each family unit is led by an old female known as the matriarch. When separate family units bond, they form kinship groups or bond groups. After puberty, male elephants tend to form alliances with other males.
Elephants are at their most fertile between the ages of 25 and 45. Calves are born after a gestation period of nearly two years. They are cared for by their mother and other young females in the group, known as allomothers.
Elephants use some vocalisations that are beyond the hearing range of humans, to communicate across large distances.

Feeding

 

African elephants can eat up to 450 kilograms of vegetation per day though their digestive system is not very efficient and only 40% of this food is properly digested. They use their trunk to pluck at leaves and their tusks to tear at branches, which can cause enormous damage.

Intelligence


African elephants are highly intelligent, and they have a very large and highly convoluted neocortex, a trait also shared by humans, apes and certain dolphin species. They are amongst the world's most intelligent species. With a mass of just over 5 kg (11 lb), elephant brains are larger than those of any other land animal, and although the largest whales have body masses twenty-fold those of a typical elephant, whale brains are barely twice the mass of an elephant's brain. The elephant's brain is similar to that of humans in terms of structure and complexity - such as the elephant's cortex having as many neurons as a human brain, suggesting convergent evolution.
Elephants exhibit a wide variety of behaviors, including those associated with grief, learning, allomothering, mimicry, art, play, a sense of humor, altruism, use of tools, compassion, cooperation, self-awareness, memory and possibly language. All point to a highly intelligent species that are thought to be equal with cetaceans and primates.

Conservation


Poaching significantly reduced the population of Loxodonta in certain regions during the 20th century. In the ten years preceding an international ban in the trade in ivory in 1990 the African elephant population was more than halved from 1.3 million to around 600,000. An example of how the ivory trade causes poaching pressure is in the eastern region of Chad. There, the estimated elephant population was 400,000 as recently as 1970, but by 2006 the number had dwindled to about 10,000. The African elephant nominally has governmental protection, but poaching for the ivory trade can devastate populations. Kenya was one of the worst affected countries with populations declining by as much as 85 percent between 1973 and 1989.
Protection of African elephants has become high profile in many countries. In 1989, the Kenyan Wildlife Service burnt a stockpile of tusks in protest against the ivory trade. A number of states permit sport hunting of elephants. A major issue in elephant conservation is the conflicts between elephants and a growing human population. Human encroachment into or adjacent to natural areas where bush elephants occur has led to recent research into methods of safely driving groups of elephants away from humans, including the discovery that playback of the recorded sounds of angry honey bees is remarkably effective at prompting elephants to flee an area.
The International Union for Conservation of Nature (IUCN) African elephant specialist group has set up a human elephant conflict working group to look at conserving a species that has potential to be detrimental to human populations. They believe that different approaches are needed in different countries and regions, and so develop conservation strategies at National and Regional levels.

Friday, 10 August 2012

Sumatran Rhinocerous

The Sumatran rhinoceros (Dicerorhinus sumatrensis) is a member of the family Rhinocerotidae and one of five extant rhinoceroses. It is the only extant species of the genus Dicerorhinus. It is the smallest rhinoceros, although is still a large mammal. This rhino stands 112–145 cm (3.67–4.76 ft) high at the shoulder, with a head-and-body length of 2.36–3.18 m (7.7–10.4 ft) and a tail of 35–70 cm (14–28 in). The weight is reported to range from 500 to 1,000 kg (1,100 to 2,200 lb), averaging 700–800 kg (1,500–1,800 lb), although there is a single record of a 2,000 kg (4,400 lb) specimen. Like the African species, it has two horns; the larger is the nasal horn, typically 15–25 centimetres (5.9–9.8 in), while the other horn is typically a stub. A coat of reddish-brown hair covers most of the Sumatran rhino's body.
Members of the species once inhabited rainforests, swamps and cloud forests in India, Bhutan, Bangladesh, Myanmar, Laos, Thailand, Malaysia, Indonesia, and China. In historical times they lived in southwest China, particularly in Sichuan. They are now critically endangered, with only six substantial populations in the wild: four on Sumatra, one on Borneo, and one in the Malay Peninsula. Their numbers are difficult to determine because they are solitary animals that are widely scattered across their range, but they are estimated to number fewer than 275. Survival of the Peninsular Malaysia population is in doubt, and one of the Sumatran populations may already be extinct. Total numbers today may be as low as 200. The decline in the number of Sumatran rhinoceros is attributed primarily to poaching for their horns, which are highly valued in traditional Chinese medicine, fetching as much as US$30,000 per kilogram on the black market.
The Sumatran rhino is a mostly solitary animal except for courtship and offspring-rearing. It is the most vocal rhino species and also communicates through marking soil with its feet, twisting saplings into patterns, and leaving excrement. The species is much better studied than the similarly reclusive Javan rhinoceros, in part because of a program that brought 40 Sumatran rhinos into captivity with the goal of preserving the species. The program was considered a disaster even by its initiator; most of the rhinos died and no offspring were produced for nearly 20 years, representing an even worse population decline than in the wild.

Taxonomy and naming


The first documented Sumatran rhinoceros was shot 16 kilometres (9.9 mi) outside Fort Marlborough, near the west coast of Sumatra, in 1793. Drawings of the animal, and a written description, were sent to the naturalist Joseph Banks, then president of the Royal Society of London, who published a paper on the specimen that year. It was not until 1814, however, that the species was given a scientific name, by Johann Fischer von Waldheim, a German scientist and curator of the State Darwin Museum in Moscow, Russia.
The scientific name Dicerorhinus sumatrensis comes from the Greek terms di (δι, meaning "two"), cero (κέρας, meaning "horn"), and rhinos (ρινος, meaning "nose"). Sumatrensis signifies "of Sumatra", the Indonesian island where the rhinos were first discovered. Carolus Linnaeus originally classified all rhinos in the genus Rhinoceros; therefore the species was originally identified as Rhinoceros sumatrensis. Joshua Brookes considered the Sumatran rhinoceros, with its two horns, a distinct genus from the one-horned Rhinoceros, and gave it the name Didermocerus in 1828. Constantin Wilhelm Lambert Gloger proposed the name Dicerorhinus in 1841. In 1868, John Edward Gray proposed the name Ceratorhinus. Normally the oldest name would be used, but a 1977 ruling by the International Commission on Zoological Nomenclature established the proper genus name as Dicerorhinus.
The three subspecies are:

D. s. sumatrensis, known as the western Sumatran rhinoceros, has only 170 to 230 rhinos remaining, mostly in the national parks of Bukit Barisan Selatan and Gunung Leuser in Sumatra. Around 75 may also live in Peninsular Malaysia. The main threats against this subspecies are habitat loss and illegal poaching. There is a slight genetic difference between the western and eastern Sumatran rhinos. The rhinos in Peninsular Malaysia were once known as D. s. niger, but were later recognized to be similar to the rhinos on western Sumatra.

D. s. harrissoni, known as the eastern Sumatran rhinoceros or Bornean rhinoceros, was once common throughout Borneo; now only about 50 individuals are estimated to survive. The known population on Borneo lives in Sabah. There are unconfirmed reports of animals surviving in Sarawak and Kalimantan. This subspecies is named after Tom Harrisson, who worked extensively with Bornean zoology and anthropology in the 1960s. The Bornean subspecies is markedly smaller than the other two.

D. s. lasiotis, known as the northern Sumatran rhinoceros, once roamed in India and Bangladesh, but has been declared extinct in these countries. Unconfirmed reports suggest there may be a small population still surviving in Burma, but the political situation in the country has prevented verification. The name lasiotis is derived from the Greek for "hairy-ears". Later studies showed their ear-hair was not longer than other Sumatran rhinos, but D. s. lasiotis remained a subspecies because it was significantly larger than the other subspecies.

Evolution


Ancestral rhinoceroses first diverged from other perissodactyls in the Early Eocene. Mitochondrial DNA comparison suggests the ancestors of modern rhinos split from the ancestors of Equidae around 50 million years ago. The extant family, the Rhinocerotidae, first appeared in the Late Eocene in Eurasia, and the ancestors of the extant rhino species dispersed from Asia beginning in the Miocene
The Sumatran rhinoceros is considered the least derived of the extant species, as it shares more traits with its Miocene ancestors.Paleontological evidence in the fossil record dates the genus Dicerorhinus to the Early Miocene, 23–16 million years ago. Many fossils have been classified as members of Dicerorhinus, but no other recent species are in the genus. Molecular dating suggests a split of Dicerorhinus from the four other extant species as far back as 25.9 ± 1.9 million years. Three hypotheses have been proposed for the relationship between the Sumatran rhinoceros and the other living species. One hypothesis suggests the Sumatran rhinoceros is closely related to the black and white rhinos in Africa, evidenced by the species having two horns, instead of one. Other taxonomists regard the Sumatran rhinoceros as a sister taxon of the Indian and Javan rhinoceros because their ranges overlap so closely. A third hypothesis, based on more recent analyses, however, suggests the two African rhinos, the two Asian rhinos and the Sumatran rhinoceros represent three essentially separate lineages that split around 25.9 million years ago, and it may therefore be unclear which group diverged first.
Because of morphological similarities, the Sumatran rhinoceros is believed to be closely related to the extinct woolly rhinoceros (Coelodonta antiquitatis). The woolly rhinoceros, so named for the coat of hair it shares with the Sumatran rhinoceros, first appeared in China, and by the Upper Pleistocene, ranged across the Eurasian continent from Korea to Spain. The woolly rhinoceros survived the last Ice Age, but like the woolly mammoth, most or all became extinct around 10,000 years ago. Although some morphological studies questioned the relationship, recent molecular analysis has supported the two species as sister taxa.

Description

 

Specimen in Cincinnati Zoo
 
A mature Sumatran rhino stands about 120–145 centimetres (3.9–4.76 ft) high at the shoulder, has a body length of around 250 centimetres (8.2 ft) and weighs 500–800 kilograms (1,100–1,800 lb), though the largest individuals in zoos have been known to weigh as much as 1,000 kilograms (2,200 lb). Like the African species, it has two horns. The larger is the nasal horn, typically only 15–25 centimetres (5.9–9.8 in), though the longest recorded specimen was much longer at 81 centimetres (32 in). The posterior horn is much smaller, usually less than 10 centimetres (3.9 in) long, and often little more than a knob. The larger nasal horn is also known as the anterior horn; the smaller posterior horn as the frontal horn. The horns are dark gray or black in color. The males have larger horns than the females, though the species is not otherwise sexually dimorphic. The Sumatran rhino lives an estimated 30–45 years in the wild, while the record time in captivity is a female D. lasiotis which lived for 32 years and 8 months before dying in the London Zoo in 1900.
Two thick folds of skin encircle the body behind the front legs and before the hind legs. The rhino has a smaller fold of skin around its neck. The skin itself is thin, 10–16 millimetres (0.39–0.63 in), and in the wild the rhino appears to have no subcutaneous fat. Hair can range from dense (the most dense hair in young calves) to scarce and is usually a reddish-brown. In the wild, this hair is hard to observe because the rhinos are often covered in mud. In captivity, however, the hair grows out and becomes much shaggier, likely because of less abrasion from walking through vegetation. The rhino has a patch of long hair around the ears and a thick clump of hair at the end of the tail. Like all rhinos, they have very poor vision. The Sumatran rhinoceros is fast and agile; it climbs mountains easily and comfortably traverses steep slopes and riverbanks. 

Distribution and habitat

 

The Taman Negara National Park contains the only known concentrated population of Sumatran rhinoceros on mainland Asia.
 
The Sumatran rhinoceros lives in both lowland and highland secondary rainforest, swamps and cloud forests. It inhabits hilly areas close to water, particularly steep upper valleys with a lot of undergrowth. The Sumatran rhinoceros once inhabited a continuous range as far north as Burma, eastern India and Bangladesh. Unconfirmed reports also placed it in Cambodia, Laos and Vietnam. All known living animals occur in Peninsular Malaysia, the island of Sumatra and Sabah, Borneo. Some conservationists hope Sumatran rhinos may still survive in Burma, though it is considered unlikely. Political turmoil in Burma has prevented any assessment or study of possible survivors. The last reports of stray animals from Indian limits were in 1990s.
The Sumatran rhino is widely scattered across its range, much more so than the other Asian rhinos, which has made it difficult for conservationists to protect members of the species effectively. Only six areas are known to contain communities of more than a handful of Sumatran rhinoceros: Bukit Barisan Selatan National Park, Gunung Leuser National Park, and Way Kambas National Park on Sumatra; Taman Negara National Park in Peninsular Malaysia; and the Tabin Wildlife Reserve in Sabah, Malaysia on the island of Borneo.
The Kerinci Seblat National Park, Sumatra's largest, was estimated to contain a population of around 500 rhinos in the 1980s, but due to poaching, this population is now considered extinct. The survival of any animals in Peninsula Malaysia is also in doubt.

A cloud forest in Sabah, Borneo
 
Genetic analysis of Sumatran rhino populations has identified three distinct genetic lineages. The channel between Sumatra and Malaysia was not as significant a barrier for the rhinos as the Barisan Mountains along the length of Sumatra, for rhinos in eastern Sumatra and Peninsular Malaysia are more closely related than the rhinos on the other side of the mountains in western Sumatra. In fact, the eastern Sumatra and Malaysia rhinos show so little genetic variance that the populations were likely not separate during the Pleistocene, when sea levels were much lower and Sumatra formed part of the mainland. Both populations of Sumatra and Malaysia, however, are close enough genetically that interbreeding would not be problematic. The rhinos of Borneo are sufficiently distinct that conservation geneticists have advised against crossing their lineages with the other populations. Conservation geneticists have recently begun to study the diversity of the gene pool within these populations by identifying microsatellite loci. The results of initial testing found levels of variability within Sumatran rhino populations comparable to those in the population of the less endangered African rhinos, but the genetic diversity of Sumatran rhinos is an area of continuing study.

Behaviour

 

Male of the extinct D. s. lasiotis with a very large front horn, London Zoo around 1904
 
Sumatran rhinoceroses are solitary creatures except for pairing before mating and during offspring rearing. Individuals have home ranges; bulls have territories as large as 50 km2 (19 sq mi), whereas females' ranges are 10–15 km2 (3.9–5.8 sq mi). The ranges of females appear to be spaced apart; males' ranges often overlap. There is no evidence Sumatran rhinos defend their territory through fighting. Marking their territory is done by scraping soil with their feet, bending saplings into distinctive patterns, and leaving excrement. The Sumatran rhino is usually most active when eating, at dawn, and just after dusk. During the day, the rhino wallows in mud baths to cool down and rest. In the rainy season, they move to higher elevations; in the cooler months, they return to lower areas in their range.
The rhino spends a large part of its day in wallows. When mud holes are unavailable, the rhino will deepen puddles with its feet and horns. The wallowing behaviour helps the rhino maintain its body temperature and protect its skin from ectoparasites and other insects. Captive specimens, deprived of adequate wallowing, have quickly developed broken and inflamed skins, suppurations, eye problems, inflamed nails, hair loss and have eventually died. One 20-month study of wallowing behavior found they will visit no more than three wallows at any given time. After two to 12 weeks using a particular wallow, the rhino will abandon it. Typically, the rhino will wallow around midday for two to three hours at a time before venturing out for food. Although in zoos the Sumatran rhino has been observed wallowing less than 45 minutes a day, the study of wild animals found 80–300 minutes (an average of 166 minutes) per day spent in wallows.

A Sumatran rhinoceros wallows in the mud at the Cincinnati Zoo.
 
There has been little opportunity to study epidemiology in the Sumatran rhinoceros. Ticks and gyrostigma were reported to cause deaths in captive animals in the 19th century. The rhino is also known to be vulnerable to the blood disease surra, which can be spread by horse-flies carrying parasitic trypanosomes; in 2004, all five rhinos at the Sumatran Rhinoceros Conservation Centre died over an 18-day period after becoming infected by the disease. The Sumatran rhino has no known predators other than humans. Tigers and wild dogs may be capable of killing a calf, but calves stay close to their mothers, and the frequency of such killings is unknown. Although the rhino's range overlaps with elephants and tapirs, the species do not appear to compete for food or habitat. Elephants (Elephas maximus) and Sumatran rhinos are even known to share trails, and many smaller species such as deer, boar and wild dogs will use the trails the rhinos and elephants create.
The Sumatran rhino maintains trails across its range. The trails fall into two types. Main trails will be used by generations of rhinos to travel between important areas in the rhino's range, such as between salt licks, or in corridors through inhospitable terrain that separates ranges. In feeding areas, the rhinos will make smaller trails, still covered by vegetation, to areas containing food the rhino eats. Sumatran rhino trails have been found that cross rivers deeper than 1.5 meters (5 ft) and about 50 meters (165 ft) across. The currents of these rivers are known to be strong, but the rhino is a strong swimmer. A relative absence of wallows near rivers in the range of the Sumatran rhinoceros indicates they may occasionally bathe in rivers in lieu of wallowing.

Diet

 

MallotesPhilipensis.jpg Garcinia mangostana fruit1.jpg
Eugenia1.jpg Ardisia crenata6.jpg
The Sumatran rhino eats a wide range of plants, such as: (clockwise from top left), Mallotus, mangosteens, Ardisia, and Eugenia.
Most feeding occurs just before nightfall and in the morning. The Sumatran rhino is a browser, with a diet of young saplings, leaves, fruits, twigs and shoots. The rhinos usually consume up to 50 kg (110 lb) of food a day. Primarily by measuring dung samples, researchers have identified more than 100 food species consumed by the Sumatran rhinoceros. The largest portion of the diet is tree saplings with a trunk diameter of 1–6 cm (0.4–2.4 inches). The rhinoceros typically pushes these saplings over with its body, walking over the sapling without stepping on it, to eat the leaves. Many of the plant species the rhino consumes exist in only small portions, which indicates the rhino is frequently changing its diet and feeding in different locations. Among the most common plants the rhino eats are many species from the Euphorbiaceae, Rubiaceae and Melastomataceae families. The most common species the rhino consumes is Eugenia.
The vegetal diet of the Sumatran rhinoceros is high in fiber and only moderate in protein. Salt licks are very important to the nutrition of the rhino. These licks can be small hot springs, seepages of salty water or mud-volcanoes. The salt licks also serve an important social purpose for the rhinos—males visit the licks to pick up the scent of females in oestrus. Some Sumatran rhinos, however, live in areas where salt licks are not readily available, or the rhinos have not been observed using the licks. These rhinos may get their necessary mineral requirements by consuming plants rich in minerals.

Communication

 




The Sumatran rhinoceros is the most vocal of the rhinoceros species. Observations of the species in zoos show the animal almost constantly vocalizing, and it is known to do so in the wild, as well. The rhino makes three distinct noises: eeps, whales, and whistle-blows. The eep, a short, one-second-long yelp, is the most common sound. The whale, named for its similarity to vocalizations of the humpback whale , is the most song-like vocalization and the second-most common. The whale varies in pitch and lasts from four to seven seconds. The whistle-blow is named because it consists of a two-second-long whistling noise and a burst of air in immediate succession. The whistle-blow is the loudest of the vocalizations, loud enough to make the iron bars in the zoo enclosure where the rhinos were studied vibrate. The purpose of the vocalizations is unknown, though they are theorized to convey danger, sexual readiness, and location, as do other ungulate vocalizations. The whistle-blow could be heard at a great distance, even in the dense brush in which the Sumatran rhino lives. A vocalization of similar volume from elephants has been shown to carry 9.8 km (6.1 mi) and thus the whistle-blow may carry as far. The Sumatran rhinoceros will sometimes twist the saplings they do not eat. This twisting behavior is believed to be used as a form of communication, frequently indicating a junction in a trail.

Reproduction

 

Adult with juvenile
 
Females become sexually mature at the age of six to seven years, while males become sexually mature at about 10 years old. The gestation period is around 15–16 months. The calf, which typically weighs 40–60 kg (88–132 lb), is weaned after about 15 months and stays with the mother for the first two to three years of its life. In the wild, the birth interval for this species is estimated to be four to five years; its natural offspring-rearing behavior is unstudied.
The reproductive habits of the Sumatran rhinoceros have been studied in captivity. Sexual relationships begin with a courtship period characterized by increased vocalization, tail raising, urination and increased physical contact, with both male and female using their snouts to bump the other in the head and genitals. The pattern of courtship is most similar to that of the black rhinoceros. Young Sumatran rhino males are often too aggressive with females, sometimes injuring and even killing them during the courtship. In the wild, the female could run away from an overly aggressive male, but in their smaller captive enclosures, they cannot; this inability to escape aggressive males may partly contribute to the low success rate of captive breeding programs.
The period of oestrus itself, when the female is receptive to the male, lasts about 24 hours, and observations have placed its recurrence between 21–25 days. Rhinos in the Cincinnati Zoo have been observed copulating for 30–50 minutes, similar in length to other rhinos; observations at the Sumatran rhinoceros Conservation Centre in Malaysia have shown a briefer copulation cycle. As the Cincinnati Zoo has had successful pregnancies, and other rhinos also have lengthy copulatory periods, a lengthy rut may be the natural behavior. Though researchers observed successful conceptions, all these pregnancies ended in failure for a variety of reasons until the first successful captive birth in 2001; studies of these failures at the Cincinnati Zoo discovered the Sumatran rhino's ovulation is induced by mating and it had unpredictable progesterone levels. Breeding success was finally achieved in 2001, 2004 and 2007 by providing a pregnant rhino with supplementary progestin. Recently, a calf was born in captivity of an endangered female in western Indonesia,only fifth such birth in one and a quarter century.

Conservation

 

D. s. sumatrensis "Rosa" in the Sumatran Rhino Sanctuary, Way Kambas National Park
 
Sumatran rhinoceroses were once quite numerous throughout Southeast Asia. It is now estimated that fewer than 275 individuals remain. The species is classed as critically endangered, primarily due to illegal poaching. Until the early 1990s, the population decline was estimated at more than 50% per decade, and the small, scattered populations now face high risks of inbreeding depression. Most remaining habitat is in relatively inaccessible mountainous areas of Indonesia.
Poaching of Sumatran rhinoceros is a cause for concern, as the price of its horn has been estimated as high as $30,000 per kilogram.This species has been overhunted for many centuries, leading to the current greatly reduced – and still declining – population. The rhinos are difficult to observe and hunt directly (one field researcher spent seven weeks in a treehide near a salt lick without ever observing a rhino directly), so poachers make use of spear traps and pit traps. In the 1970s, uses of the rhinoceros's body parts among the local people of Sumatra were documented, such as the use of rhino horns in amulets and a folk-belief that the horns offer some protection against poison. Dried rhinoceros meat was used as medicine for diarrhea, leprosy and tuberculosis. "Rhino-oil", a concoction made from leaving a rhino's skull in coconut oil for several weeks, may be used to treat skin diseases. The extent of use and belief in these practices is not known. It was once believed that rhinoceros horn was widely used as an aphrodisiac; in fact traditional Chinese medicine never used it for this purpose.Nevertheless, hunting in this species has primarily been driven by a demand for rhino horns with supposedly medicinal properties.

Close-up of specimen in Cincinnati Zoo
 
The rainforests of Indonesia and Malaysia, which the Sumatran rhino inhabits, are also targets for legal and illegal logging because of the desirability of their hardwoods. Rare woods like merbau, meranti and semaram are valuable on the international markets, fetching as much as $1,800 per m3 ($1,375 per cu yd). Enforcement of illegal-logging laws is difficult because humans live within or near many of the same forests as the rhino. The 2004 Indian Ocean earthquake has been used to justify new logging. Although the hardwoods in the rainforests of the Sumatran rhino are destined for international markets and not widely used in domestic construction, the number of logging permits for these woods has increased dramatically because of the tsunami. However, while it has been suggested that this species is highly sensible to habitat disturbance, it appears this is of little importance compared to hunting, as it can withstand more or less any forest condition.

In captivity


The female D. s. lasiotis "Begum", which was shown in London Zoo from 15 February 1872 to 31 August 1900
Though rare, Sumatran rhinoceroses have occasionally been exhibited in zoos for nearly a century and a half. The London Zoo acquired two Sumatran rhinoceros in 1872. One of these, a female named "Begum", was captured in Chittagong in 1868 and survived at the London Zoo until 1900, the record lifetime in captivity for a Sumatran rhino. Begum was also the type of the extinct subspecies D. s. lasiotis. At the time of their acquisition, Philip Sclater, the secretary of the Zoological Society of London, claimed the first Sumatran rhinoceros in zoos had been in the collection of the Zoological Garden of Hamburg since 1868. Before the extinction of the subspecies Dicerorhinus sumatrensis lasiotis, at least seven specimens were held in zoos and circuses. Sumatran rhinos, however, did not thrive outside their native habitats. A rhino in the Calcutta Zoo successfully gave birth in 1889, but for the entire 20th century, not one Sumatran rhino was born in a zoo. In 1972, Subur, the only Sumatran rhino remaining in captivity died at the Copenhagen Zoo.
Despite the species' persistent lack of reproductive success, in the early 1980s, some conservation organizations began a captive breeding program for the Sumatran rhinoceros. Between 1984 and 1996, this ex situ conservation program transported 40 Sumatran rhinos from their native habitat to zoos and reserves across the world. While hopes were initially high, and much research was conducted on the captive specimens, by the late 1990s, not a single rhino had been born in the program, and most of its proponents agreed the program had been a failure. In 1997, the IUCN's Asian rhino specialist group, which once endorsed the program, declared it had failed "even maintaining the species within acceptable limits of mortality", noting that, in addition to the lack of births, 20 of the captured rhinos had died. In 2004, a surra outbreak at the Sumatran Rhinoceros Conservation Centre killed all the captive rhinos in Peninsular Malaysia, reducing the population of captive rhinos to eight.

The taxidermied remains of the last Sumatran rhinoceros that lived in captivity by 1972, a female called "Subur"

Seven of these captive rhinos were sent to the United States (the other was kept in Southeast Asia), but by 1997, their numbers had dwindled to three: a female in the Los Angeles Zoo, a male in the Cincinnati Zoo, and a female in the Bronx Zoo. In a final effort, the three rhinos were united in Cincinnati. After years of failed attempts, the female from Los Angeles, "Emi", became pregnant for the sixth time, with the zoo's male "Ipuh". All five of her previous pregnancies ended in failure. But researchers at the zoo had learned from previous failures, and, with the aid of special hormone treatments, Emi gave birth to a healthy male calf named "Andalas" (an Indonesian literary word for "Sumatra") in September 2001. Andalas's birth was the first successful captive birth of a Sumatran rhino in 112 years. A female calf, named "Suci" (Indonesian for "pure"), followed on July 30, 2004. On April 29, 2007, Emi gave birth a third time, to her second male calf, named "Harapan" (Indonesian for "hope") or Harry. In 2007, Andalas, who had been living at the Los Angeles Zoo, was returned to Sumatra to take part in breeding programs with healthy females, leading to the siring and June 23, 2012 birth of male calf Andatu, the fourth captive-born calf of the era; Andalas had been mated with Ratu, a wild-born female living in the Rhino Sanctuary at Way Kambas National Park.
Despite the recent successes in Cincinnati, the captive breeding program has remained controversial. Proponents argue the zoos have aided the conservation effort by studying the reproductive habits, raising public awareness and education about the rhinos, and helping raise financial resources for conservation efforts in Sumatra. Opponents of the captive breeding program argue the losses are too great; the program is too expensive; removing rhinos from their habitat, even temporarily, alters their ecological role; and captive populations cannot match the rate of recovery seen in well-protected native habitats.

Cultural depictions


Aside from those few individuals kept in zoos and pictured in books, the Sumatran rhinoceros has remained little known, overshadowed by the more common Indian, black and white rhinos. Recently, however, video footage of the Sumatran rhinoceros in its native habitat and in breeding centers has been featured in several nature documentaries. Extensive footage can be found in an Asia Geographic documentary The Littlest Rhino. Natural History New Zealand showed footage of a Sumatran rhino, shot by freelance Indonesian-based cameraman Alain Compost, in the 2001 documentary The Forgotten Rhino, which featured mainly Javan and Indian rhinos.
Though documented by droppings and tracks, pictures of the Bornean rhinoceros were first taken and widely distributed by modern conservationists in April 2006, when camera traps photographed a healthy adult in the jungles of Sabah in Malaysian Borneo. On April 24, 2007 it was announced that cameras had captured the first-ever video footage of a wild Bornean rhino. The night-time footage showed the rhino eating, peering through jungle foliage, and sniffing the film equipment. The World Wildlife Fund, which took the video, has used it in efforts to convince local governments to turn the area into a rhino conservation zone. Monitoring has continued; 50 new cameras have been set up, and in February 2010, what appeared to be a pregnant rhino was filmed.
A number of folk tales about the Sumatran rhino were collected by colonial naturalists and hunters from the mid-19th century to early 20th century. In Burma, the belief was once widespread that the Sumatran rhino ate fire. Tales described the fire-eating rhino following smoke to its source, especially campfires, and then attacking the camp. There was also a Burmese belief that the best time to hunt was every July, when the Sumatran rhinos would congregate beneath the full moon. In Malaya, it was said that the rhino's horn was hollow and could be used as a sort of hose for breathing air and squirting water. In Malaya and Sumatra, it was once believed that the rhino shed its horn every year and buried it under the ground. In Borneo, the rhino was said to have a strange carnivorous practice: after defecating in a stream, it would turn around and eat fish that had been stupefied by the excrement.

Thursday, 9 August 2012

Przewalski

Przewalski's horse or Dzungarian horse, is a rare and endangered subspecies of wild horse (Equus ferus) native to the steppes of central Asia, specifically Mongolia. At one time extinct in the wild (in Mongolia, the last wild Przewalski's horses had been seen in 1966), it has been reintroduced to its native habitat in Mongolia at the Khustain Nuruu National Park, Takhin Tal Nature Reserve  and Khomiin Tal. The taxonomic position is still debated, and some taxonomists treat Przewalski's horse as a species, Equus przewalskii.
Common names for this equine include Asian wild horse, Przewalski's Wild Horse,Mongolian wild horse and the Tahki. Historical but obsolete names include true tarpan and Mongolian tarpan. The horse is named after the Russian geographer and explorer Nikolai Przhevalsky.
Most "wild" horses today, such as the American Mustang or the Australian Brumby, are actually feral horses descended from domesticated animals that escaped and adapted to life in the wild. In contrast, Przewalski's horse has never been successfully domesticated and remains a truly wild animal today. Przewalski's horse is one of three known subspecies of Equus ferus, the others being the domesticated horse, Equus caballus and the extinct tarpan (Equus ferus ferus). The Przewalski's horse is considered the only remaining truly wild "horse" in the world and may be the closest living wild relative of the domesticated horse. There are still a number of other wild equines, including three species of zebra and various subspecies of the African wild ass, onager (including the Mongolian wild ass) and kiang.

Taxonomy

 

The Przewalski's horse was described in 1881 by L.S. Poliakov. The taxonomic position of Przewalski's horse has always been problematic and no consensus exists whether it is a full species (Equus przewalskii), a subspecies of the wild horse (Equus ferus przewalskii) or even a sub-population of the horse (Equus ferus). Studies using DNA have been inconclusive, in part due to crossing domestic horses into the Przewalski's horse as well as the limited genetic variation present in the founder population of the Przewalski's horse. A 2009 molecular study using ancient DNA (that is DNA recovered from archaeological finds like bones and teeth) places the Przewalski's horse in the middle of the domesticated horses, but more recent mitochondrial DNA analysis suggests that the Przewalski and the modern domestic horse diverged some 160,000 years ago. The karyotype of the domestic horse differs from that of Przewalski’s horse by an extra chromosome pair either because of the fission of domestic horse chromosome 5 in Przewalski’s horse or fusion of Przewalski’s horse chromosomes 23 and 24 in the domestic horse. In comparison, the chromosomal differences between domestic horses and zebras include numerous translocations, fusions, and inversions. Przewalski’s horse is known to have the highest diploid chromosome number among all equine species. Przewalski’s horse can interbreed with the domestic horse and produce fertile offspring (65 chromosomes) 

Population

 

The world population of these horses are all descended from 9 of the 31 horses in captivity in 1945. These nine horses were mostly descended from approximately 15 captured around 1900. A cooperative venture between the Zoological Society of London and Mongolian scientists has resulted in successful reintroduction of these horses from zoos into their natural habitat in Mongolia; and as of 2011 there is an estimated free-ranging population of over 300 in the wild. The total number of these horses according to a 2005 census was about 1,500.

Appearance

 

Przewalski's horse is stockily built in comparison to domesticated horses, with shorter legs. Typical height is about 13 hands (52 inches, 132 cm), length is about 2.1 m (6 ft 11 in). They weigh around 300 kilograms (660 lb). The coat is generally dun in color with pangaré features, varying from dark brown around the mane (which stands erect) to pale brown on the flanks and yellowish-white on the belly and around the muzzle. The legs of Przewalski's horse are often faintly striped, also typical of primitive markings. The tail is about 90 cm (35.43 in) long, with a longer dock and shorter hair than seen in domesticated horses.

Behavior

 

Przewalski's horses
In the wild, Przewalski's horses live in small, permanent family groups consisting of one adult stallion, one to three mares, and their common offspring. Offspring stay in the family group until they are no longer dependent, usually at 2 or 3 years old. Bachelor stallions, and sometimes old stallions, join bachelor groups. Family groups can join together to form a herd that move together.
The patterns of their daily lives exhibit horse behavior similar to that of feral horse herds. Stallions herd, drive and defend all members of their family, while the mare often displays leadership in the family. Stallions and mares stay with their preferred partner for years.
Horses maintain visual contact with their family and herd at all times and have a host of ways to communicate with one another, including vocalizations, scent marking, and a huge range of visual and tactile signals. Each kick, groom, tilt of the ear or other contact with another horse are means of communicating. This constant communication leads to complex social behaviors among Przewalski's horses. 

History

 

In the 15th century, Johann Schiltberger recorded one of the first European sightings of the horses in the journal of his trip to Mongolia as a prisoner of the Mongol Khan. The horse is named after the Russian colonel Nikolai Przhevalsky (1839–1888) (the name is of Polish origin and "Przewalski" is the Polish spelling). He was the explorer and naturalist who first described the horse in 1881, after having gone on an expedition to find it, based on rumors of its existence. Many of these horses were captured around 1900 by Carl Hagenbeck and placed in zoos. As noted above, about twelve to fifteen reproduced and formed today's population.


The native population declined in the 20th century due to a combination of factors, with the wild population in Mongolia dying out in the 1960s. The last herd was sighted in 1967 and the last individual horse in 1969. Expeditions after this failed to locate any horses, and the species was designated "extinct in the wild" for over 30 years.
After 1945 only two captive populations in zoos remained, in Munich and in Prague. The most valuable group, in Askania Nova, Ukraine, was shot by German soldiers during World War II occupation, and the group in the USA had died out.
By the end of the 1950s, only 12 individual Przewalski's horses were left in the world.

Przewalski's horses
 
In 1977, the Foundation for the Preservation and Protection of the Przewalski horse was founded in Rotterdam, the Netherlands, by Jan and Inge Bouman. The Foundation started a program of exchange between captive populations in zoos throughout the world to reduce inbreeding, and later began a breeding program of its own. As a result of such efforts, the extant herd has retained a far greater genetic diversity than its genetic bottleneck made likely.
In 1992, sixteen horses were released into the wild in Mongolia, followed by additional animals later on. One of the areas to which they were reintroduced became Khustain Nuruu National Park in 1998. Another reintroduction site is Great Gobi B Strictly Protected Area, located at the fringes of the Gobi desert. Lastly, in 2004 and 2005, 22 horses were released by the Association Takh to a third reintroduction site in the buffer zone of the Khar Us Nuur National Park, in the northern edge of the Gobi ecoregion.
The reintroduced horses successfully reproduced, and the status of the animal was changed from "extinct in the wild" to "endangered" in 2005. On the IUCN Red List, they were reclassified from "extinct in the wild" to "critically endangered" after a reassessment in 2008 and from "critically endangered" to "endangered" after a 2011 reassessment.

Preservation efforts

 

Close up image
 
While dozens of zoos worldwide have Przewalski's horses in small numbers, there are also specialized reserves dedicated primarily to the species.
The world's largest captive breeding program for Przewalski's horses is at the Askania Nova preserve in Ukraine. Several dozen Przewalski's horses were also released in the area evacuated after the Chernobyl accident, which now serves as a deserted de facto natural preserve.An intensely researched population of free-ranging animals was also introduced to the Hortobágy puszta in Hungary; data on social structure, behavior and diseases gathered from these animals is used to improve the Mongolian conservation effort.
Several American zoos also collaborated in breeding Equus ferus przewalskii from 1979 to 1982. Recent advances in equine reproductive science in the USA also have potential to further preserve and expand the gene pool. In October 2007, scientists at the Smithsonian Institution's National Zoo successfully reversed a vasectomy on a Przewalski's horse — the first operation of its kind on this species and possibly the first ever on any endangered species. While normally a vasectomy may be performed on an endangered animal under limited circumstances, particularly if an individual has already produced many offspring and its genes are overrepresented in the population, scientists realized the animal in question was one of the most genetically valuable Przewalski's horses in the North American breeding program.
Le Villaret, located in the Cevennes National Park in southern France and run by the Association Takh, is a breeding site for Przewalski Horses that was created to allow the free expression of natural Przewalski's horse behaviors. Eleven zoo born horses were brought to Le Villaret in 1993. Horses born there are adapted to life in the wild: they are free to choose their own mates and must forage on their own. Such a unique breeding site was necessary to produce the individuals that were reintroduced to Mongolia in 2004 and 2005. In 2012 there were 39 individuals at Le Villaret. 
The Przewalski's Horse Reintroduction Project of China was initiated in 1985 when 11 wild horses were imported from overseas. After more than two decades of effort, the Xinjiang Wild Horse Breeding Centre has bred a large number of the horses, of which 55 were released into the Kalamely Mountain area. The animals quickly adapted to their new environment. In 1988, six foals were born and survived, and by 2001 there were over 100 horses at the centre.

Wednesday, 8 August 2012

Vaquita

The vaquita (Phocoena sinus) is a rare species of porpoise. It is endemic to the northern part of the Gulf of California. Estimates of the number of individuals alive range from 100  to 300. The word "vaquita" is Spanish for little cow. Since the baiji (Lipotes vexillifer) is believed to have gone extinct in 2006, the vaquita has taken on the title of the most endangered cetacean in the world.
Other names include Cochito, Gulf of California Harbor Porpoise, Gulf of California Porpoise, Gulf Porpoise, Hafenschweinswal, and Marsouin du Golfe de Californie

Biology

 

Physical description

 

The Vaquita has a classic porpoise shape (stocky and curved into a star shape when viewed from the side). It is the smallest of the porpoises, a group of marine mammals that differ from dolphins in their stockier, robust body, lack of an elongated beak, and their distinctively shaped teeth. Individuals may reach a mature size of 1.2-1.5 m (4-5 ft) and may weigh 40-55 kg (90-120 lb). They have large black eye rings and lip patches. The upper side of the body is medium to dark grey. The underside is off-white to light grey but the demarcation between the sides is indistinct. The flippers are proportionately larger than in other porpoises and the fin is taller and more falcate. The skull is smaller and the rostrum is shorter and broader than in other members of the genus.

Habitat

 

The habitat of the vaquita is thought to be restricted to the northern area of the Gulf of California. The vaquita lives in shallow, murky lagoons along the shoreline and is rarely seen in water much deeper than 30 meters; indeed, it can survive in lagoons so shallow that its back protrudes above the surface. The vaquita is most often sighted in water 11 to 50 metres deep, 11 to 25 kilometres from the coast, over silt and clay bottoms. Its habitat is characterised by turbid water with a high nutrient content. Other characteristics of its habitat are strong tidal mixing, convection processes and high primary and secondary productivity.

Behavior

 

There are very few records of the Vaquita in the wild. It appears to swim and feed in a leisurely manner, but is elusive and will avoid boats of any kind. It rises to breathe with a slow, forward-rolling movement that barely disturbs the surface of the water, and then disappears quickly, often for a long time. It has an indistinct blow, but makes a loud, sharp, puffing sound reminiscent of the Harbour Porpoise.

Schooling

 

Like other phocoenids, the vaquita occurs singly or in small groups, usually from 1 - 3 individuals but as many as 8 - 10.

Diet

 

All of the 17 fish species found in vaquita stomachs can be classified as demersal and or benthic species inhabiting relatively shallow water in the upper Gulf of California, and it appears that the vaquita is a rather non-selective feeder on small fishes and squids in this zone. Like other cetaceans, the vaquita produces high-frequency clicks which are used in echolocation. This may be used to locate their prey, but several of the fish species it feeds on are known to produce sound and so it is possible that the vaquita locates them by following their sound, rather than by echolocating.

Reproduction

 

Most calving apparently occurs in the spring. Gestation is probably 10–11 months. Maximum observed life span was 21 years.

Conservation

 

Vaquita have never been hunted directly. Indeed their continued existence was only confirmed by a dedicated survey in 1985. However, it is known that the vaquita population is declining. Estimates have placed the vaquita population at 567 in 1997 and 150 in 2007. The decline in the vaquita population is believed to be due to the animals becoming trapped in gillnets intended for capturing another species endemic to the Gulf, the totoaba. CIRVA, the Committee for the Recovery of the Vaquita, concluded in 2000 that between 39 and 84 individuals are killed each year by such gillnets. The Vaquita is listed by the IUCN and the Convention on International Trade in the Endangered Species of Wild Fauna and Flora in the most critical category at risk of extinction. In order to try to prevent extinction, the Mexican government has created a nature reserve covering the upper part of the Gulf of California and the Colorado River delta. CIRVA is recommending that this reserve be extended southwards to cover the full known area of the Vaquita's range and that trawlers be completely banned from the reserve area. Even if the number of Vaquita killed by fisheries is reduced to zero, concerns remain amongst conservationists. Use of chlorinated pesticides, reduced flow of freshwater from the Colorado River due to irrigation, and depression due to inbreeding may also have a detrimental effect.
The Vaquita is one of the top 100 EDGE Species, meaning "Evolutionarily Distinct, Globally Endangered". Evolutionarily distinct animals have no close relatives and represent proportionally more of the tree of life than other species, meaning they are top priority for conservation campaigns.
On October 28, 2008, Canada, Mexico, and the United States, under the jurisdiction of the NAFTA environmental organization, the Commission for Environmental Cooperation, launched the North American Conservation Action Plan (NACAP) for the Vaquita. The NACAP is a strategy to support Mexico’s efforts to recover the Vaquita, which is considered the world’s most-endangered marine mammal. The U.S. government has listed the vaquita as endangered under the Endangered Species Act.