Eli5: how is it that so many species, including humans, have the same motherly instinct that suddenly appears after birth? Where does this come from?

Question

Eli5: how is it that so many species, including humans, have the same motherly instinct that suddenly appears after birth? Where does this come from?

In: 2

Answer 1

Survival of the species. Mothers who did not foster/protect their offspring had offspring that died and could not pass along the traits needed to have successful offspring. Basically, if your children cannot immediately take care of themselves after birth (like most fish and insects) and the maternal instinct to care for them until they can care for themselves doesn’t kick in, that genetic line ceases to exist because the offspring never reproduces.