Animal Domestication Correlates With A Lower Stress Response

lvysaur

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http://blogs.scientificamerican.com/thoughtful-animal/monday-pets-the-russian-fox-study/

"The experimental foxes had significantly lower adrenaline levels than their control-group cousins."


Animal evolution during domestication: the domesticated fox as a model

the reduction in exploratory activity, which, as noted above, sets an end to the sensitive socialization period, was found to be correlated with a rise in plasma cortisol level during early postnatal development.(40) In the tame pups, whose socialization period was longer, this rise occurred later

The basal cortisol levels in the blood of the domesticated foxes in generation 20 were almost twofold lower than of the non-domesticated, and it was about 30% lower under stress. In generation 45, basal and stress-induced blood cortisol levels in foxes of the tame population were already three- and fivefold lower than in the farm-bred foxes.
 
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lvysaur

lvysaur

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Yellow jackets are famed for their aggression, while Mud Dauber wasps are famed for their lack of aggression. Yellow jackets mature very quickly and are very fertile, while Mud Daubers mature very slowly and have extremely low litter numbers. Paper wasps are noted to be intermediate in aggression, and they are also intermediate in reproductive status.

Many of the extinct huge birds (Dodo, Moa, etc.) had very low brood sizes as well, and were noted to be remarkably unafraid of humans.

I think human evolution itself is more or less an instance of a "K selected" organism being able to eliminate its susceptibility to predation.
 

milkboi

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I think human evolution itself is more or less an instance of a "K selected" organism being able to eliminate its susceptibility to predation.

Of course humans are K selected, the most K selected of all species.
 

thomas00

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Koalas that live in urban regions have lower cortisol than those than live in the wilderness


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lvysaur

lvysaur

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Of course humans are K selected, the most K selected of all species.
Well yes, but I was referring to the evolutionary processes.

When we were exiled from the trees, we undoubtedly faced great predation. And this predation would have kept us (back then some form of hominid or even ape) in an r-selected form.

So what probably happened was that some groups of apes had a nice predator-free environment, while most were evolving into smaller and more adrenergic forms, to avoid predation on the plains.

This allowed the former groups to develop higher cultural and biological faculties, which would have been maladaptive in the latter group. When the former "K" groups colonized predator-rich environments, their higher culture/toolmaking allowed them to survive, and the r selected were outcompeted.
 

milkboi

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Well yes, but I was referring to the evolutionary processes.

When we were exiled from the trees, we undoubtedly faced great predation. And this predation would have kept us (back then some form of hominid or even ape) in an r-selected form.

So what probably happened was that some groups of apes had a nice predator-free environment, while most were evolving into smaller and more adrenergic forms, to avoid predation on the plains.

This allowed the former groups to develop higher cultural and biological faculties, which would have been maladaptive in the latter group. When the former "K" groups colonized predator-rich environments, their higher culture/toolmaking allowed them to survive, and the r selected were outcompeted.

Sounds plausible :)
 

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