African wild dog
The African wild dog, also called painted dog and Cape hunting dog, is a wild canine native to sub-Saharan Africa. It is the largest wild canine in Africa and the only extant member of the genus Lycaon, which is distinguished from Canis by dentition highly specialised for a hypercarnivorous diet and by a lack of dewclaws.
An estimated 6,600 adults live in 39 subpopulations, all threatened by habitat fragmentation, human persecution, and outbreaks of disease. As the largest subpopulation probably consists of fewer than 250 individuals, the African wild dog has been listed as endangered on the IUCN Red List since 1990.
The African wild dog is a specialized hunter of terrestrial ungulates, mostly hunting at dawn and dusk, but it also displays diurnal activity. It captures its prey by using stamina and cooperative hunting to exhaust them. Its natural competitors are lions and spotted hyenas; the former kill the dogs where possible, whilst the latter are frequent kleptoparasites. Like other canids, the African wild dog regurgitates food for its young, but also extends this action to adults as a central part of the pack's social unit. The young have the privilege of feeding first on carcasses.
The African wild dog has been revered in several hunter-gatherer societies, particularly those of the San people and prehistoric Egypt.
Etymology and naming
The English language has several names for the African wild dog, including African hunting dog, Cape hunting dog, painted hunting dog, painted dog, painted wolf, and painted lycaon. Though the name African wild dog is widely used, "wild dog" is thought by conservation groups to have negative connotations that could be detrimental to its image; one organisation promotes the name "painted wolf",whilst the name "painted dog" has been found to be the most likely to counteract negative perceptions.
Taxonomic and evolutionary history
Taxonomy
The earliest written reference for the species appears to be from Oppian, who wrote of the thoa, a hybrid between the wolf and leopard, which resembles the former in shape and the latter in colour. Solinus's Collea rerum memorabilium from the third century AD describes a multicoloured, wolf-like animal with a mane native to Ethiopia.The African wild dog was scientifically described in 1820 by Coenraad Jacob Temminck after examining a specimen from the coast of Mozambique, which he named Hyaena picta. It was later recognised as a canid by Joshua Brookes in 1827 and renamed Lycaon tricolor. The root word of Lycaon is the Greek λυκαίος, meaning wolf-like. The specific epithet pictus, which derived from the original picta, was later returned to it, in conformity with the International Rules on Taxonomic Nomenclature.
Paleontologist George G. Simpson placed the African wild dog, the dhole, and the bush dog together in the subfamily Simocyoninae on the basis of all three species having similarly trenchant carnassials. This grouping was disputed by Juliet Clutton-Brock, who argued that other than dentition, too many differences exist among the three species to warrant classifying them in a single subfamily.
Evolution
The African wild dog possesses the most specialized adaptations among the canids for coat colour and diet and for pursuing its prey through its cursorial ability. It has a graceful skeleton, and the loss of the first digit on its forefeet increases its stride and speed. This adaptation allows it to pursue prey across open terrain for long distances. The teeth are generally carnassial-shaped, and its premolars are the largest relative to body size of any living carnivoran with the exception of the spotted hyena. On the lower carnassials, the talonid has evolved to become a cutting blade for flesh slicing, with a reduction or loss of the postcarnassial molars. This adaptation also occurs in the two other hypercarnivorous canids – the dhole and the bush dog. The African wild dog exhibits some of the most varied coat colours among mammals. Individuals differ in patterns and colours, indicating a diversity of the underlying genes. The purpose of these coat patterns may be an adaptation for communication, concealment, or temperature regulation. A 2019 study indicated that the lycaon lineage diverged from Cuon and Canis 1.7 million years ago through this suite of adaptations, and these occurred at the same time as large ungulates diversified. The findings also suggest that the African wild dog is largely isolated from gene transfer with other canid species.The oldest African wild dog fossil dates back to 200,000 years ago and was found in HaYonim Cave, Israel. The evolution of the African wild dog is poorly understood owing to the scarcity of fossil finds. Some authors consider the extinct Canis subgenus Xenocyon as ancestral to both the genus Lycaon and the genus Cuon, which lived throughout Eurasia and Africa from the Early Pleistocene to the early Middle Pleistocene. Others propose that Xenocyon should be reclassified as Lycaon. The species Canis ''falconeri shared the African wild dog's absent first metacarpal, though its dentition was still relatively unspecialised. This connection was rejected by one author because C''. falconeris lack of the first metacarpal is a poor indication of phylogenetic closeness to the African wild dog, and the dentition was too different to imply ancestry.
Another ancestral candidate is the Plio-Pleistocene Lycaon sekowei of South Africa on the basis of distinct accessory cusps on its premolars and anterior accessory cuspids on its lower premolars. These adaptions are found only in Lycaon among living canids, which shows the same adaptations to a hypercarnivorous diet. L. sekowei had not yet lost the first metacarpal absent in L. pictus and was more robust than the modern species, having 10% larger teeth.
Admixture with the dhole
The African wild dog has 78 chromosomes, the same number as those of species in the genus Canis. In 2018 whole genome sequencing was used to compare the dhole with the African wild dog. Strong evidence was found of ancient genetic admixture between the two species. Today, their ranges are remote from each other, but during the Pleistocene era, the dhole could be found as far west as Europe. The study proposes that the dhole's distribution may have once included the Middle East, from where it may have admixed with the African wild dog in North Africa. However, no evidence has been found of the dhole having existed in the Middle East or North Africa.Subspecies
, five subspecies are recognised by Mammal Species of the World:| Subspecies | Description | Synonyms |
| Cape wild dog L. p. pictus Temminck, 1820 | The nominate subspecies is also the largest, weighing. It is much more colourful than the East African wild dog, although even within this single subspecies, large geographic variations in coat colour occur; specimens inhabiting the Cape are characterised by the large amount of orange-yellow fur overlapping the black, the partially yellow backs of the ears, the mostly yellow underparts and a number of whitish hairs on the throat mane. Those in Mozambique are distinguished by the almost equal development of yellow and black on both the upper and underparts of the body, as well as having less white fur than the Cape form. | cacondae, fuchsi, gobabis, krebsi, lalandei, tricolor, typicus, venatica, windhorni, zuluensis |
| East African wild dog L. p. lupinus Thomas, 1902 | This subspecies is distinguished by its very dark coat with very little yellow. | dieseneri, gansseri, hennigi, huebneri, kondoae, lademanni, langheldi, prageri, richteri, ruwanae, ssongaeae, stierlingi, styxi, wintgensi |
| Somali wild dog L. p. somalicus Thomas, 1904 | This subspecies is smaller than the East African wild dog, has shorter and coarser fur and has a weaker dentition. Its colour closely approaches that of the Cape wild dog, with the yellow parts being buff. | luchsingeri, matschie, rüppelli, takanus, zedlitzi |
| Chadian wild dog L. p. sharicus Thomas and Wroughton, 1907 | Brightly coloured with very short hair. Brain case is fuller than L. p. pictus. | ebermaieri |
| West African wild dog | The West African wild dog used to be widespread from western to central Africa, from Senegal to Nigeria. Now, only two subpopulations survive, one in the Niokolo-Koba National Park of Senegal and the other in the W National Park of Benin, Burkina Faso, and Niger. It is estimated that 70 adult individuals are left in the wild. | mischlichi |
Although the species is genetically diverse, these subspecific designations are not universally accepted. East African and Southern African wild dog populations were once thought to be genetically distinct, based on a small number of samples. More recent studies with a larger number of samples showed that extensive intermixing has occurred between East African and Southern African populations in the past. Some unique nuclear and mitochondrial alleles are found in Southern African and northeastern African populations, with a transition zone encompassing Botswana, Zimbabwe, and southeastern Tanzania between the two. The West African wild dog population may possess a unique haplotype, thus possibly constituting a truly distinct subspecies. The original Serengeti and Maasai Mara population of painted dogs is known to have possessed a unique genotype, but these genotypes may be extinct.