The report on the second part of the series, the one I just watched, is also interesting.
Tonight's program discussed the way in which we have bred dogs to suit our requirements, often neglecting their best interests. Of course, that makes me think once more about the fact that Penny tore her cruciate ligament. If it's as prevalent in domesticated dogs as it's reported to be, I'd be interested to know how frequently it happens in the wild.
One particularly wild dog is the African wild dog. In the program Clunes visited a program aiming at releasing a pack of these endangered dogs back into the wild. Interestingly, even though they had been reared by the man Clunes visited, they did not relate to him at all. According to him, dogs in general relate to their human companions by figuring out how the humans fit into the dogs' idea of a pack. But African wild dogs will not integrate a newcomer into an existing pack, so they will never relate to humans. If the pack leader dies, his son is then the next pack leader.
I wanted to read more about this, because I can't figure out how it works. Surely a pack must accept outsiders, or else inbreeding will take place. Perhaps it's just that outsiders can't be pack leader.
At a site called Naturalia there's plenty of information. It appears that a new pack forms when young sibling females leave their pack to look for some males. The males they meet will be related to each other, so the new pack has only one breeding pair, with the 'uncles' and 'aunts' helping to raise the pups. The really fascinating thing is that the new pack is organised on age class, not individual status. Perhaps this is something to do with the choice of pack leader. I'll have to read the rest of the information.
Perhaps this also explains a sad part of the Clunes program, where an older female tried to join the newly forming pack and had to be saved from death by the intervention of humans.