From Wikipedia:

“Homo homini lupus, or in its unabridged form Homo homini lupus est, is a Latin proverb meaning “A man is a wolf to another man,” or more tersely “Man is wolf to man.” It has meaning in reference to situations where people are known to have behaved in a way comparably in nature to a wolf. The wolf as a creature is thought, in this example, to have qualities of being predatory, cruel, inhuman i.e. more like an animal than civilized.”

No mammals kill their own, but humans.

Shame is on the human race. Cannibalistic habits and behavior.