Dingo

2008/9 Schools Wikipedia Selection. Related subjects: Mammals

Dingo
Dingo (Canis lupus dingo)
Conservation status
Vulnerable ( IUCN 3.1)
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Carnivora Family: Canidae Genus: Canis Species: C. lupus Subspecies: C. l. dingo
Trinomial name
Canis lupus dingo ( Meyer, 1793)
Dingo range

The Dingo (Canis lupus dingo) or Warrigal is a type of Australian canid, which was thought to be descended from the Iranian Wolf (Canis lupus pallipes); however, DNA analysis has shown it to be more closely related to domestic dogs, suggesting that they were introduced from a small population of domesticated dogs, possibly at a single occasion during the Austronesian expansion into Island Southeast Asia. It is commonly described as an Australian wild dog, but is not restricted to Australia, nor did it originate there. Modern dingoes are found throughout Southeast Asia, mostly in small pockets of remaining natural forest, and in mainland Australia, particularly in the north. They have features in common with both wolves and modern dogs, and are regarded as more or less unchanged descendants of an early ancestor of modern dogs. The name dingo comes from the language of the Eora Aboriginal people, who were the original inhabitants of the Sydney area. The New Guinea Singing Dog is also classified as Canis lupus dingo.

Description

Appearance

Adult dingoes are typically 19–23 inches (48–58 cm) tall at the shoulders, and weigh on average 50–70 pounds (23–32 kg), though specimens weighing 120 pounds (55 kg) have been recorded. Males are larger and heavier than females. Dingoes in southern Australia tend to be smaller than dingoes occurring in northern and north-western Australia. Australian dingoes are invariably larger than specimens occurring in Asia. Compared to similarly sized domestic dogs, dingoes have longer muzzles, larger carnassials, longer canine teeth, and a flatter skull with larger nuchal lines. Their dental formula is 3/3-1/1-4/4-2/3=42. Dingoes lack the same degree of tooth crowding and jaw-shortening that distinguishes other dog breeds from wolves.

Fur colour is typically yellow-ginger, though tan, black, white or sandy including occasional brindle can occur. Albino dingoes have been reported. Any other colours are indicators of hybridization. Purebred Dingos have white hair on their feet and tail tip and lack dewclaws on their hindlegs.

Chromosome number is 2n=78.

Temperament and behaviour

Dingoes are mostly seen alone, though the majority belong to packs which rendezvous once every few days to socialise or mate. Scent marking, howling and stand offs against rival packs increase in frequency during these times. Packs of dingoes can number 3 to 12 in areas with little human disturbance, with distinct male and female dominance hierarchies determined through aggression. Successful breeding is typically restricted to the dominant pair, though subordinate pack members will assist in rearing the puppies.

The size of a dingo's territory has little to do with pack size, and more to do with terrain and prey resources. Dingoes in south-western Australia have the largest home ranges. Dingoes will sometimes disperse from the natal home ranges, with one specimen having been recorded to travel 250 kilometers.

Dingoes do not bark as much as domestic dogs, which can be very loud, and they howl more frequently. Three basic howls with over 10 variations have been recorded. Howling is done to attract distant pack members and it repels intruders. In chorus howling, the pitch of the howling increases with the number of participating members. Males scent mark more frequently than females, peaking during the breeding season.

Ecology

Reproduction

Like wolves, but unlike domestic dogs, dingoes reproduce once annually. Male dingoes are fertile throughout the year, whereas females are only receptive during their annual estrus cycle. Females become sexually mature at the age of two years, while males obtain it at 1 to 3 years. Dominant females within packs will typically enter estrus earlier than subordinates. Captive dingoes typically have a pro-estrus and estrus period lasting 10–12 days, while for wild specimens it can be as long as 2 months. The gestation period lasts 61–69 days, with litters usually being composed of 5 puppies. There is usually a higher ratio of females than males. Puppies are usually born from May to July, though dingoes living in tropical habitats can reproduce at any time of the year. Hybrid dingoes often enter estrus twice annually, and have a gestation period of 58–65 days. Puppies are usually born in caves, dry creekbeds or appropriated rabbit or wombat burrows. Puppies become independent at 3–6 months, though puppies living in packs will sometimes remain with their group until the age of 12 months. Unlike in wolf packs, in which the dominant animals prevent subordinates from breeding, alpha dingoes suppress subordinate reproduction through infanticide.

Dietary habits

Dingoes feeding on human handouts in Borneo

Over 170 different animal species have been recorded in Australia to be included in the dingo's diet, ranging from insects to water buffalo. Prey specialisation varies according to region. In Australia's northern wetlands, the most common prey are magpie geese, dusky rats and agile wallabies, while in arid central Australia, the most frequent prey items are european rabbits, long-haired rats, house mice, lizards and red kangaroos. In north-western habitats, Eastern Wallaroos and red kangaroos are usually taken, while wallabies, possums and wombats are taken in the east and south eastern highlands. In Asia, dingoes live in closer proximity to humans, and will readily feed on rice, fruit and human refuse. Dingoes have been observed hunting insects, rats and lizards in rural areas of Thailand and Sulawesi. Dingoes will usually hunt alone when targeting small prey such as rabbits and will hunt in groups for large prey like kangaroos. Dingoes in Australia will sometimes prey on livestock in times of seasonal scarcity.

Relationship with invasive species

In Australia, dingoes compete for the same food supply as introduced feral cats and foxes, and also prey upon them (as well as on feral pigs). A study at James Cook University has concluded that the reintroduction of dingoes would help control the populations of these pests, lessening the pressure on native biodiversity. The author of the study, Professor Chris Johnson, notes his first-hand observations of native rufous bettongs being able to thrive when dingoes are present. The rate of decline of ground-living mammals decreases from 50% or more, to just 10% or less, where dingoes are present to control fox and cat populations.

Conservation Status

As a result of interbreeding with dogs introduced by European settlers, the purebred dingo gene pool is in decline. By the early 1990s, about a third of all wild dingoes in the south-east of the continent were dingo/domestic dog crosses, and although the process of interbreeding is less advanced in more remote areas, the extinction of the subspecies in the wild is considered inevitable. Although protection within Federal National Parks, World Heritage areas, Aboriginal reserves, and the Australian Capital Territory is available for dingoes, they are at the same time classified as a pest in other areas. Since a lack of country-wide protection means they may be trapped or poisoned in many areas, in conjunction with the hybridisation with domestic dogs the taxon was upgraded from 'Lower Risk/Least Concern' to 'Vulnerable' by the IUCN (International Union for the Conservation of Nature and Natural Resources) in 2004.

Relationships with humans

Origins and Western recognition

Dingoes were transported from mainland Asia, through South-East Asia to Australia and other parts of the Pacific by Asian seafarers throughout their voyages over the last 5,000 years. Dingos arrived in Australia around 3,500–4,000 years ago, quickly spreading to all parts of the Australian mainland and offshore islands, save for Tasmania. The dogs were originally kept by some Australian native groups as an emergency food source.

The arrival of dingoes is thought by some to have been a major factor in the extinction of the thylacine in mainland Australia. Fossil evidence and Aboriginal paintings show that thylacines once inhabited the entire Australian mainland, only to suddenly disappear about 3,000 years ago. Seeing as dingoes are thought to have arrived around 500 years prior, certain people think this was sufficient time for the canids to impact on mainland thylacine populations, either through interspecific competition or through the diffusion of disease. Seeing as thylacines managed to survive in the dingo-devoid island of Tasmania until the 1930s, some put this forward as further indirect evidence for dingo responsibility for the thylacine's disappearance. Some however doubt the impact of the dingo, as the two species would not have been in direct competition with one another. The dingo is a primarily diurnal predator, while it is thought the thylacine hunted mostly at night. In addition, the thylacine had a more powerful build, which would have given it an advantage in one-to-one encounters.

European settlers did not discover dingoes until the 17th century, and originally dismissed them as feral dogs. Captain William Dampier, who wrote of the wild dog in 1699, was the first European to first officially note the dingo. Dingo populations flourished with the European's introduction of domestic sheep and European rabbit to the Australian mainland.

Dingoes as pets

Currently, dingo puppies are only available within Australia and it is illegal to export them, though this may change through the urgings of breed fanciers. Puppies can cost from AU$500–1,000. Although dingoes are generally healthier than most domestic dogs, and lack the characteristic "doggy odour", they can become problematic during their annual breeding season, particularly males which will sometimes attempt to escape captivity in order to find a mate. Some Aborigines will prevent a dingo they have become attached to from escaping by breaking its front legs.

Attacks on humans

Although humans are not natural prey for wild dingoes, there have been a number of instances in which people have been attacked by them. Currently, the most famous fatality case is that of 10 week old Azaria Chamberlain, who was thought to have been taken by a dingo on the 17th April 1980 on Ayers Rock. The body itself was never found, and the child's mother was found guilty of murder until released on appeal. All other recorded attacks occurred on Fraser Island, where dingoes have become habituated to humans feeding them. This has lead to an increase in agressive encounters between dingoes and humans. Between 1996 and 2001, 224 incidences of dingoes biting people were recorded, and on the 17th of May 2001, a 9 year old boy was killed, leading to the shooting of 40 dingoes.