martinh wrote:
In addition, hunting is something that was best done collectively (at least until the game was wiped out of most places).Hunting is best done collectively, but in a population of collective hunters a selfish 'free rider' who doesn't join in will have a genetic advantage, so collective hunting by non-kin does not occur. The possible exception of this might be a kind of tit-for-tat coperation which we will get to in chapter 12, but that can only be very limited - it might explain lionesses who aren't genetically related hunting together for example (I think this occurs?). I would argue that there are no examples in nature of animals hunting together who are not either closely related or have been in regular contact with one another for long enough (eg through being 'wives' in a lion's 'harem') to build up a limited amount of reciprocal 'trust' on a personal level).
Well I'd agree that there is no hunting by groups of animals who are not either closely related or have been in regular contact, that's fairly obvious. However, I think a selfish free rider would be dealt with by the group hunting - if an individual is just along for the ride, the self-interest of the others would be to exclude it from feeding. Everyone has self-interest - not just those who are "selfish". And the benefits of co-operation are clear - lions hunting as a pride can tackle prey like buffalo, hippo and elephant, as well as the larger antelopes. Single lions stick to the smaller game. A pride can defend its kill against other animals - a single animal can't. In fact, it's noticeable that the most solitary hunter among African fauna, the cheetah, is the animal most likely to have its kill stolen.
Regards,
Martin
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Having mulled this over I think what I am getting at is that there is a relationship between what cultures do and genetics, though I don't think it is a direct relationship abd certainly not a determinist one. But there certainly is one and taboos, for example, are ways of a society codifying this. A good example being societies having a pretty universal (I don't know enough to say it is universal) taboo against brother-sister relatinships, but no similar universal taboo about cousins. (and before the jokes about East Anglia/Royston Vasey/Tasmania start, we should perhaps remember that Darwin married his cousin, so it's not as alien to our own society as we might imagine).
I don't know about the Ibo example, but I would speculate that at some point in the past that society has gone through some sort of crisis where infant mortality became unsustainable and that this process became assimilated into the practices of the culture, possibly as strong as a taboo. A further speculation might be that twins are less likely to both survive anyway, because of the added stress on the mother feeding them. While multiple births are not a problem in the modern age, there wasn't formula milk a century ago, nor cows/goats/sheeps milk in plenty of other societies. Once the babies are weaned, this ceases to be an issue, but until then a crisis situation would be tougher for twins. *
Anyway, as a general rule, I think some behaviours in societies are genetically favoured, and genetically influenced, though not genetically determined. And, as Dawkins points out, we can over-ride our genes.
Regards,
(A hopefully clearer) Martin
*As an aside, I'm not a fan of boycotts but avoid Nestle products for the baby milk dumping they do on the third world. A company prepared to directly kill children for profit deserves all it gets.