Wild dogs have a reputation they no longer deserve. Distant relatives of man's best friend, these carnivores once hunted antelopelike animals across the open plains of East Africa for tens of kilometers before taking their quarry down as a group. But that's not how they operate today. A 5-month study of wild dogs wearing special tracking collars shows that these animals tend to stick to short chases, rarely, if ever, coordinating their hunting—a strategy that may help the endangered species survive.
Wild dogs—brown- and black-spotted, big-eared distant relatives of dogs and wolves that stand less than a meter tall—used to be common throughout much of Africa, but a couple hundred years ago people began shooting them as vermin. Now, just 7000 remain. Most live on wooded or partially wooded savanna, not open plains. Conservationists have struggled to help this species recover, but packs can roam hundreds of kilometers, making them difficult to keep track of.
Alan Wilson, a biomechanist at the Royal Veterinary College, Hertfordshire, in the United Kingdom, first became interested in wild dogs when he was studying cheetahs. Often praised as the fastest land animal on the planet, the cheetah tends to hunt and feed alone, capturing antelope, impala, and other prey with short bursts of incredible agility and rapid acceleration, his team found in 2013. Wild dogs (Lycaon pictus) live in the same places and eat the same foods as these big cats, but supposedly hunt much differently.
To compare the efficiency of the two strategies, Wilson and his colleagues put battery- and solar-powered GPS collars on all six adult members of a wild dog pack in Botswana and on a few wild dogs from a dozen other packs. (They shy away from people—their primary predator—but are approachable by car, which they seem to have no fear of.) The collars also had sensors that detect how fast the animal is moving. By recording and mapping the simultaneous movement of the six animals, Wilson's team could reconstruct the pack's activity.
"The application of [these] new technologies allow greater insights into the study of a species that is hard to observe and moves over great distances," says Joshua Ginsberg, a wildlife ecologist at the Cary Institute of Ecosystem Studies in Millbrook, New York, who was not involved with the work.
All together, the tags catalogued more than 1500 runs of up to 3 meters per second—a fast trot—and during two-thirds of them, the wild dog more than doubled its speed temporarily, indicating it was chasing an impala, dik-dik, or other prey down. They never approached the maximum speed of a cheetah, about 29 meters per second, but often sustained a chase almost twice the distance as the big cat. The researchers almost never saw two or more wild dogs homing in on the same spot during a chase, they report online today in Nature Communications. But once the chase was over, the team knew when the quarry was caught because other dogs quickly converged to share that food and stayed in one place for a while, following a strict pecking order with respect to which pack member eats first.
Thus, the current strategy for these wild dogs seems to be that rather than chasing down a few large prey by traveling long distances at low speeds, they go after a lot of different prey, using short bursts of speed to run them down. In these endeavors, they are successful less than 16% of the time, Wilson finds. But because impala are often too much for one wild dog to eat, food sharing helps make up for inefficient hunting, Wilson adds. So although they still live as packs, they don’t seem to cooperate in the hunting, only in the eating.
In a second paper in Nature Communications, Wilson and his colleagues calculate the energy expended by cheetahs or wild dogs to hunt and the energy gained from catching and eating prey. Cheetahs use athleticism and bring down large animals that they rarely finish off, whereas dogs are less efficient. They make up for their inefficiency by having multiple hunters, each of which sometimes catches prey big enough to share, the researchers report.
The work "shows wild dogs can significantly alter their hunting strategies to meet the challenges of different habitats," Ginsberg says. That's good news for saving wild dogs, he adds, as "it shows that they are able to live across a diversity of habitats." So perhaps with even with their fewer numbers, wild dogs will do OK in the long run.