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
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