[Scandiravian]

If a sufficiently large part of a population behaves altruistically, it does makes sense for adoption to happen.

In the example with the elephant seals, if a mother becomes separated from her calf during a storm, having a predisposition in the population to adopting someone else's calf is beneficial to the mother, as her offspring might be adopted as well

[pron]

Natural selection is not about the phenotype. It is not beneficial to the mother to have "her genes" propagate. Natural selection works on a gene-by-gene basis and, if anything, the genes "use" the individual as a carrier serving their "benefit", not the other way around. Even more precisely, it's about genes becoming more or less widespread in the population. A gene doesn't "care" what happens to one of its carriers. You gain nothing by spreading "your" genes; your genes, however, may use you as a vehicle to spread themselves.

The question is, then, if there is some gene that encourages adoption, will such a gene spread in the population or not? I'm not sure I see why it would. However, if such a trait is already spread in the population, especially if it's not a specific gene but an outcome of others, indeed I don't think there would be selective pressure working against it for the reason you mentioned.

[dTal]

>You gain nothing by spreading "your" genes; your genes, however, may use you as a vehicle to spread themselves.

Getting philosophical here, but what does it even mean for me to "gain something", given that my entire existence is a conglomeration of mostly-cooperating genes trying to spread themselves, and my values, desires, and outlook on life are heavily controlled by said genes? Spreading my genes is the intrinsic value, from which all my other instrumental values like eating tasty food, making good friends, enjoying sex etc are derived.

[MrMcCall]

Yes. As well, prey animals also have better safety with greater numbers.

[jstanley]

That's not how natural selection works.

[ujikoluk]

It is though, at the group level. The groups that adopt will have better survival than groups that don't, if the environment is such that parents regularly die while the cubs are small.

[dukeyukey]

At an individual level, no. At a group level, yes.

[Toine]

Please explain since you seem to have a PhD in darwinism.

[vibrio]

Check your assumptions.