African Wild Dog
African Wild Dog
With no more sound than a breeze stirring leaves in a dry woodland, a pack of African wild dogs roams tirelessly through its vast home range. The pack moves as one; individuals pause only occasionally to investigate a noteworthy scent detected in passing on a microcurrent of warm air. Consummately cooperative, the dogs are described most succinctly by two fundamental behavioral characteristics: cohesive sociality and mobility.
Keeping Up with the Pack
Form and Function
The African hunting dog is the least typical canid. It is exclusively carnivorous and has a relatively short, powerful muzzle housing an array of shearing teeth, with the last molar poorly developed; unlike other canids, it has lost the fifth digit – the dew claw – on the front feet. The distinctive, large, rounded ears probably aid cooling, but also emphasize the role of vocal signals in social contact. A wild dog will often find itself separated from pack members by some distance soon after the start of a hunt. The pack remain in touch by using soft, distinctive contact calls – “hoo” – that they can detect from as far as 2km (1.2mi) away. Pack members will reassemble after short periods of separation by tracking the direction and distance of the calls.
Despite relying on visual contact to pursue prey, wild dogs hunt in the low light of dawn and dusk, taking advantage of the cool conditions. They also hunt at night during periods of bright moonlight. Packs will rally and move off to hunt twice every day, but an average pack successfully captures prey only twice every three days.
Wild dogs hunt a wide range of species, from rabbits to buffalo calves and zebras. They are best adapted to pursuing medium-sized antelopes; in southern Africa, impalas constitute as much as 85 percent of wild dog prey, with numerous species making up the remainder. Some packs specialize on prey species that others rarely hunt. In the Serengeti, for example, two packs of dogs have been known to hunt zebras. In northern Botswana warthogs and ostriches are relatively common, but only a few packs have the skills to capture them.
A hunt begins with a lethargic rally after the dogs have rested through the heat of the day. They start with a ritual greeting, complete with begging, face licking, and excited vocalizations from the young dogs. Shortly after the greeting, the pack starts walking away stiffly in a direction usually chosen by one or two of the older dogs, followed by the others spread out in a loose string. In a few minutes they pick up the pace to a steady, near-effortless trot, a gait they can maintain for hours in cool temperatures.
The primary method of capture is to pursue the prey until it tires, enabling a dog to grab it by the flank and pull it to the ground. Over open ground, wild dogs have been recorded running at speeds of 60km/h (37mph). It is common in bushy habitat for a single wild dog to make a kill and then return to fetch the reassembled pack. More often, additional pack members will join in the kill, having kept pace during the chase. Sometimes the entire pack is right behind at the moment of capture. In these circumstances a medium-sized antelope will be dispatched and consumed by all the dogs present. They eat in an exuberance of frenetic excitement and a flurry of dust, which belies the cooperation and precision with which they carve.
The Caring Carnivore
African wild dogs hunt, rest, travel, and reproduce in packs, which average seven or eight adult members but may include anything from two to more than thirty. Packs of over 50 individuals occur but rarely endure for more than a few months. When they swell to numbers in excess of 30 with pups from a third or fourth litter, packs usually break up. This normally happens midway through the year, either through fission or, more commonly, via dispersal of single-sex groups.
Packs are formed when a group of females joins an unfamiliar group of males. An average new pack consists of two sisters from one pack – usually littermates – and three or four brothers from another. A dominant pair, consisting of one male and one female, emerges immediately to lead the new coalition. Occasionally these new groups fail to coalesce into a functioning pack, whereupon the males and females separate. More often they thrive and establish a new range.
Wild dogs tend to mate seasonally. Reproduction is monopolized by the dominant male and female. Most subdominant adults never actually raise their own young, cooperating instead to provision the pups produced once a year by the dominant pair. They are often uncles or aunts of the pups, however, so in evolutionary terms they have a vested interest in the survival of the youngsters with which they share their genes. The dogs find a suitable den site, such as a hole dug by an aardvark or porcupine, and within 70 days of the pack forming, a litter of pups is born. Wild dogs have the largest litters among canids, with an average of 10 pups.
By 4–5 weeks of age, pups begin to eat meat regurgitated for them by the adults in the pack. They are weaned by 10 weeks. At 14–16 weeks it becomes impossible for the adults to go hunting without some or all of the pups following them. If they go astray on a hunt, they are retrieved by the adults, and are led to each kill as soon as it is made. There, the pups are allowed to eat first until they have had their fill. Only then do the adults allow themselves whatever is left of the carcass.
Physiologically mature at 13–14 months, wild dogs rarely reproduce before two years of age. All dogs surviving to one year remain in their natal pack and assist in the provisioning and protection of younger siblings. Females tend to disperse in their second year, while males are more likely to wait until the following year. When males emigrate from their natal pack they do so in larger sibling groups – the average is three but as many as eight brothers have been recorded dispersing together – and they disperse twice as far as the females.
Although their preferred habitat is woodland and scrub, wild dogs have been recorded in widely varying environments. Where healthy resident prey populations exist, wild dog densities average only one pack per 400sq km (150sq mi), while in less optimal habitats, densities as low as one per 2,000sq km (770sq mi) are not uncommon.
Running for their Lives
Conservation and Environment
The entire population of wild dogs is estimated to be less than 5,500. They are persecuted by humans and are run over by cars; they are susceptible to epidemic diseases, especially rabies; and the dogs' habitat is shrinking in face of an expanding human population. In addition, lions can pose a serious predation threat.
Wild dogs also suffer from losing food to scavenging hyenas. Dogs normally hunt for around 3.5 hours per day, but must increase this to 12 hours if they lose 25 percent of their food, which would increase their metabolic rate to a physiologically unfeasible 12 times the basal metabolic rate. They need vast areas of land on which to hunt and invariably conflict with the owners of free-ranging, unattended livestock.
A handful of substantial, but largely isolated, populations remain in east and southern Africa, along with several smaller populations through-out sub-Saharan Africa. The future of the species will depend on prevention of direct persecution, as well as on the management of land with their interests in mind. Those countries where African wild dogs do survive and prosper will be able to take pride in their habitat management for a species with very particular needs.
Factfile - African Wild Dog
Wild dog, Painted, or Cape hunting dog
Sole member of genus
Africa, from the Sahara to S Africa.
From semidesert to alpine zones; savanna woodland probably preferred.
Head–body length 75–120cm (30–47in); tail length 30–44cm (12–18in); shoulder height 75cm (30in): weight 20–32kg (44–71lb). No variation between sexes. Dogs from S African populations are consistently larger than E African.
Short and dark, with a unique pattern of irregular white and yellow blotches on each individual; muzzle dark; white-tipped tail.
Gestation 70–73 days.
About 10 years.
Endangered, with fewer than 5,500 surviving animals.
A Hunting Tradition
A zebra stallion trots away from his group of mares and foals as the wild dog pack approaches. The zebra – head lowered, teeth bared, and nostrils flaring – charges at the dogs leading the pack, who turn and flee.
This is usually what happens when African wild dogs and zebras meet. But not always. A minority of wild dog packs will attack zebras. When they do, it is the dogs who charge first, to cause a stampede before the stallions can take the initiative. Then they mount a closely coordinated attack, one dog grabbing the chosen victim's tail and another its upper lip, while the rest of the pack disembowel it.
Of 10 wild dog packs studied on the Serengeti Plain in Tanzania, only two had the ability to turn the tables on an adult zebra – eight times a dog's weight – and kill it. These two zebra-hunting packs were large, both containing eight or more adult members. Pack size, however, was not the crucial factor: three other packs of similar size ignored zebras and, on one occasion, just four dogs from a zebra-hunting pack were observed to kill a zebra.
Why then do not all African wild dog packs hunt zebras? A clue to the answer seems to lie in the fact that one of the two zebra-hunting packs contained descendents of a pack lineage that had been known to hunt zebras for at least 10 years, and over three generations. For this pack, zebra-hunting was a tradition, learned by each generation from its predecessor. Other packs studied did not exhibit any such hunting tradition, although some did show a preference for Grant's gazelles over Thomson's gazelles.
Not only zebra hunting but also such knowledge as the location of water, prey concentrations, and range boundaries may be passed on as a tradition. Studies of African wild dogs (and also of some monkeys) indicate that man's previously supposed unique reliance on cultural as against genetic inheritance should rather be viewed as a dramatic extension of a pattern that exists in other social animals.