Yes of course but animals kill out of necessity and are led by basic (and precise) instincts. And this not war in any way.
Humans, on the other hand, have logical thinking. We usually don’t kill in order to survive. We kill for reasons that are quite irrational and absurd (like religious differences for example). The worst wars in human history, took place for quite illogical reasons by a “logical” being.
That is why war is a unique phenomenon that occurs only in the human race.
Also animals, rarely if ever assasinate their own kind. We do this all the time. And even an animal is never a real assasin. A human is.
This act of assasination which needs careful planing and evil thinking (something unique to humans) is the main difference between humans and the rest of the primates of nature. And the meaning of the word “murderous” applies specifically to humans while you can give it to another primate metaphorically but not literally, I think.