The benefits of group living
In
nature there are two fundamental explanations for why animals might live in
groups: to improve the amount or quality of what they eat and/or to decrease
the probability of being eaten. In the past, speculation about the ultimate
function of group living for African wild dogs has focused predominantly on
benefits associated with enhanced access to food through co-operative hunting.
However, single dogs are able to capture prey as efficiently as groups of dogs
and, in Botswana, breeding pairs without helpers have been observed successfully
whelping litters of pups while provisioning them from their kills in exactly
the same way that a larger pack does. However, most of these packs eventually
failed, not because the pair could not feed the pups, but because either the
adults or the pups were killed by lions before the pups reached an age where
they could contribute as adults to their own and their parents' protection.
The
fact that African wild dogs commonly fall prey to lions makes it plausible that
wild dogs live in packs primarily in response to intense lion predation pressure.
Wild dogs in packs can more effectively avoid predation by lions as a result
of the increased probability of detecting a predator. Therefore, as with most
social species, increased vigilance is an extremely important function of the
social organisation of wild dogs. All
dogs, unless physically compromised, are constantly attentive to noises and
activities around them, even when they are resting. The wild dog pack also provides
an important buffer against predation by the principle of dilution - the theory
that being in a group lowers the probability of being captured since a predator
can only capture a single individual at a time. From the perspective of any
individual in the pack, the probability of its being the one captured decreases
the more members there are in the group. From the perspective of an average
wild dog pack and its collective reproductive success, the loss of a single
individual does not usually translate into total reproductive failure, as it
usually does for just a pair of wild dogs.