Endangered Dhole
| Dhole[1] Fossil range: Post Pleistocene[2]-Recent |
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| Binomial name | ||||||||||||||||
| Cuon alpinus (Pallas, 1811) |
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 Dhole range
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The Dhole (Cuon alpinus), also known as the Asiatic Wild Dog, Indian Wild Dog, or Red Dog, is a species of Asian canid, and the only member of the genus Cuon.
Physiology
Description
The Dhole has many physical similarities to the African Wild Dog and the Bush Dog, most notably in the redundancy of the post-carnassial molars, though whether this is an example of convergence or close relationship is a matter of debate.[2]
The Dhole typically weighs 12–20 kilograms (26–44 lb)[2] and measures 90 centimetres (35 in) in body length and 50 centimetres (20 in) shoulder height.[4] The tail measures 40–45 centimetres (16–18 in) in length.[4] There is little sexual dimorphism.[2] The Dhole has a broad, domed skull and a short, broad muzzle. The bones of the forehead and upper jaw are "swollen", producing a dish-faced profile. The hooded eyes have amber or light brown irises, and the ears are large and rounded.[citation needed]
The pelage of the back and flanks is red to brown in colour, while the foreneck, chest and undersides are white or lightly gingered.[2] The fur of specimens from southern ranges is typically short and rusty red, while that of more northern subspecies is longer and more yellow or brown in colour.[2] Dholes from Thailand are more uniform brown, and lack the typical lighter throat and chest, while those from Himalayan regions have more yellowish fur.[2]
Dhole dentition is unique among canids, by the fact that it has one fewer lower molars, amounting to 40 teeth rather than the more usual 42 of other species. Its lower carnassials also sport only one cusp (two is more usual for canids), an adaptation thought to improve shearing ability, thus allowing it to compete more successfully with kleptoparasites.[2] Its front pawpads are fused at the base. Females have 6-7 pairs of mammae, as opposed to the more usual five present in other canid species.[2] The chromosome number is 2n = 78.[2]
Reproduction
Sexual dimorphism is not very distinct with no quantitative anatomical differences known. Both males and females become sexually active at one year old, though females usually breed at 2 years in captivity, and in the wild, for the first time at 3 years, possibly due to physiological and behavioural restraints. Females exhibit seasonal polyoestrus, with a cycle of around 4–6 weeks. Pups are born throughout the end of fall, winter, and the first spring months ( November - March ) - dens are earthen burrows, or are constructed amongst rocks and boulder structures, in rocky caverns, or close to streambeds. In East Java, the Dhole is thought to mate mainly between January and May. Unlike some other canid species, the Dhole does not engage in a copulatory tie when mating.[5] Also, mating is not as restricted to certain individuals as it is in wolf packs, in which usually only the dominant pair can breed.[5]
After a gestation period of around 60–62 days, females usually give birth to about eight pups (though the range is 5-10, the record is 12, and sizes vary drastically within the same pack through different years), which weigh 200-350g. Dhole growth rate is faster than that of wolves, being similar in length to that of the coyote.[5] At 10 days their body weight has doubled, and body length is 340mm. Pups are weaned between 6 and 9 weeks. In captivity, weaning is sometimes recorded later on in the range. By 8 weeks, younglings are less quarrelsome and aggressive, and more vigilant. At three months litters go on hunts, though the pack may not be fully mobile until eight months. Young reach sexual maturity at about a year, and full adult size at 15 months.
After birth, a few other adults will help to feed the young of the dominant pair. The pups, as early as the age of three weeks, and the mother are fed regurgitated meat. When lone females breed, rearing the litters only results in limited success.
Diseases
Dholes are in danger of catching infectious diseases when they come in contact with other animals, especially canines – including feral and domestic dogs. They have been known to suffer from mange, canine distemper, and trypanosomiasis. Canine parvovirus was recorded in Dhole populations in Hodenhagen, Germany and Chennai, India zoos. Sporadically, the Dhole is a health risk for human beings, since their excreta contain transmittable pathogens (e.g. Toxocara canis). Dhole waste has also been found to contain roundworm, cestodes, and other endoparasites. Like other canines, the Dhole can catch rabies; in the 1940s, rabid Dholes bit and infected villagers in the Biligirirangan Hills in India.
Taxonomy
Evolution
The Dhole is a glacial period survivor like the Gray Wolf. During the glacial period, the Dhole ranged across Eurasia and North America. A canid called the Sardinian Dhole (Cynotherium sardous) lived on the Mediterranean island of Sardinia during the Pleistocene, but it is not as closely related to the living species as its name would imply.[6] A comparative study on dhole and other Canid mtDNA in 1997 showed that dholes diverged from the Lupus lupus lineage before the Black-backed Jackal (Canis mesomelas) and the Golden Jackal (Canis aureus) diverged, a couple of million years before the domestication of the dog.[7]
Subspecies
There are three recognized subspecies of the Dhole, although several others have been proposed and described, spanning different sizes and colors.[1]
- Cuon alpinus alpinus : includes populations adustus, antiquus, clamitans, dukhunensis, fumosus, grayiformis, infuscus, javanicus, laniger, lepturus, primaevus, rutilans
- alpinus: found in Eastern Russia (east of eastern Sayans), including Amur, has a thick tawny-red coat with a grayish neck and an ochre muzzle
- adustus: found in Northern Myanmar and Indo-China, has a reddish-brown coat
- dukhunensis: found South of the Ganges in India, has a red coat, short hair on the paws, and black whiskers
- fumosus: found in Western Szechuan, China, and Mongolia, has a luxuriant yellowish-red coat with a dark back and gray neck
- infuscus: found in Southern Myanmar, Malaysia, Thailand, and Vietnam has a dark brown coat and distinctive cranial features
- javanicus: found in Java, has a short, bright red coat, though there are regional variations
- laniger: found in Kashmir and Southern Tibet, has a full yellow-gray coat
- lepturus: found South of the Yangze in China, has a uniform red coat with thick under-fur
- primaevus: found in Himalayan regions of Nepal, Sikkim (India), and Bhutan, has a longer, redder coat than dukhunensis, and has long hair on the paws
- sumatrensis: found in Sumatra, has a short, bright red coat and dark whiskers
- hesperius: found in Eastern Turkestan, Southern Siberia and Western China (Altai and Tienshan), has a long, bright yellow coat with a white underside and pale whiskers
Range and habitat
The Dhole originates from South Asia. Its range is latitude: 10° South to 55° North; Longitude: 70° East to 170° East. Its historical range extended from India to China, and down to Malaysia and Indonesia, with Java as the Southern limit. In recent decades, there has been huge habitat loss in this region, and restricted surveys indicate serious decline and fragmentation of the former range. The Dhole's current range extends from the borders of Russia and the Altai Mountains in Manchuria (Central and Eastern Asia) to Northern and Western Pakistan to the forest tracts of India, Burma, and the Malayan Archipelago. The best remaining populations are probably to be found in Central (especially in the Highlands), Western and Northern Pakistan and Southern India.
The Dhole exploits a large variety of habitats. It normally inhabits dry and moist deciduous forests and thick jungles, as well as tropical rain forests, which all provide better cover for hunting. It inhabits areas of primary, secondary, degraded, evergreen, and semi-evergreen forms of vegetation, and dry thorn forests, as well as scrub-forest mosaics. It can also, however, survive in dense alpine forests, meadows and on the open steppes of Kashmir and Manchuria. As the second part of its Latin name, alpinus, suggests, the Dhole is often found in hilly or mountainous regions. The Dhole likes open spaces and during the day they can often be found on jungle roads and paths, river beds, and in jungle clearings. The Dhole inhabits in the widest range of climates in the canid family – from freezing cold to tropical heat, but is not recorded in deserts.
Factors which influence habitat include water, the presence of other large predators (competition), sufficient prey (plentiful medium to large ungulate prey species), local human population, and suitable breeding sites.
Behavior
Social behavior
The Dhole is a highly social and co-operative animal, like the Gray Wolf, the Amazonian Bush Dog, and the African Hunting Dog. Generally it lives in organized, extended-family packs of five to twelve individuals (this number rarely exceeds twenty five), with more males, sometimes twice as many more, than females, and usually just one breeding female. Sometimes pack members interact with other Dholes outside of their own group; these interactions may be positive or hostile (home ranges are often quite separate). Environmental conditions can affect group size and composition. Large packs of over forty Dholes have been sighted, possibly resulting from the temporary fusion of neighboring packs. Older Dholes of around 7–8 years sometimes vanish from the group.
Within Dhole packs, there is almost never any aggression – there is a strict social hierarchy, so fighting is not needed - or bullying, save for play-fighting among cubs. Each pack contains a dominant monogamous pair, who are usually the sole breeders. However, junior males may display sexual interest in the dominant female, and sometimes father cubs. Pack members play together regularly, allow grooming, mock-fighting, and rolling around. Social rank is reinforced by shoving and holding, rarely by biting. Dispersal is female-biased.
Within a group, members over-mark each other's waste, creating individual latrines in the home range. These latrines serve intra-group communication, for example, passing on information concerning sexual status. Video footage has been taken of a Dhole urinating while balancing only on the two front paws.
Vocalizations
The Dhole has some extraordinary vocal calls. It can make high-pitched screams, mew, hiss, squeak, yelp, chatter, and cluck like a chicken. Growl-barks and other noises alert pack-mates to danger; the large range of calls like these may have evolved to warn companions of different dangers - human, tiger, etc. Calls also act as threats to scare off enemies. Its best-known sound is its strange whistle, likened by early naturalists to the sound obtained when air is blown over an empty cartridge. These calls are used for contact within the pack. The repetitive whistles are so distinct that individual Dholes can be identified by it, and the source is easily located. Whistles travel well at ground level due to their frequency and structure.
Dietary habits
The Dhole is primarily a diurnal hunter, though it is not uncommon for it to hunt by night too.[8] Solitary Dholes usually limit themselves to small prey such as Chital fawns and Indian Hares, while a pair or trio of Dholes suffices to kill medium sized ungulates such as deer in 2 minutes.[8] Dholes will on rare occasions attack young gaur and water buffalo. Because of their thick skin around the neck, gaur and buffalo are killed through repeated bites to the muzzle, as well as dissembowelment. This method is also used in attacking tigers.[9] There is at least one account of a Dhole pack managing to pull down an Indian Elephant calf, despite ferocious defence from the mother resulting in multiple Dhole deaths.[10] The Dhole manages to avoid competition with the Leopard and the Tiger by targeting smaller prey and hunting in daylight, unlike the nocturnal felids.[5] The Dhole hunts by scent, and vocalises very little compared to wolves when attacking prey[11]. It kills large prey in a manner similar to the African Wild Dog, disemboweling and eating the prey whilst it is still alive.[8] The Dhole can eat up to 4 kilograms (8.8 pounds) of meat in an hour, and will compete with one another over a kill through speed of eating rather than fighting.[8] It typically consumes the heart, liver, eyeballs, rump and fetus first.[8] The Dhole drinks frequently after eating, and will actively search for a water source once it has eaten sufficiently.[8] Seasonal scarcity of food is not as much an issue to the Dhole as it is to wolves, so there is less of a rigid dominance hierarchy during feeding.[5] Unlike some canids, the Dhole does not cache its food. Though the majority of its food is obtained by hunting, it will occasionally scavenge from Leopard and Tiger kills.[8] The Dhole has on occasion been observed hunting with pariah dogs.[5]
Possible relationship with the domestic dog
Some researchers have doubted the predominant theory that domestic dogs are descended from wolves, and have put forward the dhole as a possible progenitor.[12] In 1857 Brian Houghton Hodgson argued that the dhole was the dog's ancestor, since it is possible to tame dholes if they are caught young, while adults are untameable.[13] Points raised in favour of the dhole ancestry cite the general domestic dog-like passiveness of the dhole in having its kills taken by humans, which contrasts with the behaviour of sympatric wolves, which will defend their prey aggressively against humans. It is also claimed that dhole skulls bear more similarities to dog skulls than wolves do, with the glaring exception of the dentition.[12]
Population pressures
It is estimated that 2,500 mature individuals remain in the wild (mainly in wildlife sanctuaries and protected national parks) and the declining population trend is expected to continue.
One major threat to the Dhole is habitat destruction (and thus loss of prey which is aggravated by deer poaching). In India alone, over 40,000 square kilometres (4,000,000 ha) of forest has disappeared in the last 20 years. Also, in Vietnam, few natural forested areas over 50 square kilometres (5,000 ha) remain. The main factors in this were logging, firewood collection, flooding due to dam construction, and agricultural expansion. Habitat deterioration fragments the Dhole population resulting in problems like disease (it is unclear whether this is a significant problem in Indo-China and Indonesia but definitely depletes the population in South Asia) and inbreeding, which have more permanent effects. Dhole habitat is also being transformed like in Sumatra.
Human persecution also contributes to the Dhole's decline (medicinal uses of the Dhole in areas such as China should be looked into). Indiscriminate snaring ("by-catch") and other non-selective hunting techniques have devastating results. The Dhole is regarded as vermin – on rare occasions, Dholes attack livestock at the cost of the owner, e.g., in Arunachal Pradesh - and has therefore been shot, trapped and poisoned (e.g., from strychnine). British colonial hunters also shot and poisoned Dhole-killed prey-carcasses because the canine was seen as a threat to local wild ungulate densities.
However, prejudice towards the Dhole still exists. Levels of persecution vary regionally depending on cultural principles, wildlife law enforcement and the intensity of livestock predation. Levels of persecution in Laos, Vietnam, and Cambodia are especially high. Upset farmers have been known to club pups to death at den sites (breeding and pup-rearing is sometimes inadvertently disrupted, as well).
Hunting and trapping for fur is not recorded as a significant contributor to the Dhole's decline perhaps because it is not numerous. In the 19th century, Dhole-fur was valuable in Ussuryisk Krai, and moving into the 20th century they were pricey in Manchuria. Nowadays, the odd Dhole-skin is recorded as a curio. Currently, there is no known widespread exploitation of the pelts. Dhole mortalities as a result of road-kill are highest in India where many roads and trails cut through its habitat.
With suitable areas steadily diminishing and cattle being grazed within the forests, livestock occasionally fall prey to the Dhole. If protection is not rigidly enforced, stockmen retaliate by excavating the den and clubbing the pups to death. Generally, Dholes ignore domestic animals, but when its natural prey is diminished, starvation ensues. In India, farmers get compensated if there is definitive proof that their livestock has been killed by Dholes outside core protected areas.
The Dhole also sometimes preys on threatened species. For example, the Banteng numbers in Alas Purwo National Park (Java) were decreasing drastically due to Dhole predation. In the end, the Dhole population fell when Banteng were not numerous enough to support them. In Kanha, India, the Dhole preys on a rare, endemic subspecies of the Barasingha. Of course, it is primarily habitat loss that has pushed both these predators and prey towards endangerment and possible extinction.
Depletion of the Dhole's prey animal populations is another problem. In much of the Dhole's habitat, even in protected areas, ungulate populations are low. In Laos, Cambodia, and Vietnam, many species larger in size than a hare have been reduced significantly because of hunting. Muntjacs and southern serow are some of the few species that haven’t been severely affected. Prey numbers in Indonesia are also low.
Further pressures are applied by local villagers who steal the Dhole's kills for their own pot as Dholes do not attack humans and retreat at the sight of one. In this way, the Dhole has become an indirect food source for the people of the jungle. People who have been recorded scavenging Dhole-kills include Kuruma tribes of the Nilgiri Hills in the south of India and at least one Mon Khmer-speaking tribe (Laos). In other regions, such as Russia, poisons set out for wolves might be responsible for declines in the local Dhole population.
Conservation
In India, bounties were paid for carcasses right up until when the Dhole was declared a protected species under Schedule 1 of the Wildlife Act of 1972 which prohibits the killing of wildlife except in self-defense; or if the Dhole is a man-killer – and, even then, permission is required. Hunting of the Dhole in the Soviet Union had been prohibited since 1971; it received the status of ‘protected animal’ in 1974.
In Vietnam, the Dhole is protected to a certain degree which limits extraction and utilization though levels of extraction and utilization are not quoted. In Cambodia, the Dhole is protected from hunting. A new forestry law is under preparation and a proposal to list the Dhole as a fully protected species is being discussed, although there appears to be no date set for its ratification. Also, large protected areas have been declared in Laos. The creation of Project Tiger Reserves has given some protection to the "dukhenesis" population. Project Tiger could potentially maintain Dhole prey-animal levels in Tiger-Dhole inhabited regions.
There are about 110 dholes in captivity (including in Dresden, Beijing, Winnipeg, and Howletts), with an even ratio of males to females. There are no current research programs investigating dholes. There have been no attempts to reintroduce the Dhole yet.
In 2009, the conservation effort at Howletts was set back when all of the Dholes managed to escape. The majority of them were recaptured, although several had to be shot[why?] by armed police.[14]