Humans, animals and pets (and the trees and the stones) are one world and one nature.

Humans are the ones who have responsibility for that nature. This means their human sisters and brothers and also their animal sisters and brothers.

If they neglect and kill the other players in nature then at the end they will kill themselves.

This is a plain and simple answer that tries not to be provocative while your question comes over plain and simple but is meant to provoke.