Why is human life valued more than animal life in the absence of religion? Are arguments based on our being intelligent or sentient valid, after all we make the rules. If you could ask an elephant it might offer other criteria to value species by.
Some people value their pets more than other people, but one reason for holding that morality protects human beings more than other animals is that morality only governs the behavior of human beings, that is, in order to persuade all human beings to follow the moral rules prohibiting killing, causing pain, etc., all human beings must know that they have the protection of the moral rules. Neither elephants nor any other non-human animals that we know about have any criteria for valuing species. And morality is not related to species either; if there were another species that was required to abide by the moral rules, the members of that species would also be protected by the moral rules.