I don't think the suttas / sutras say specifically. But we can infer from some things that are found in the Tripitaka.
*Plants are considered one-facultied, not part of rebirth, but still should not be harmed by monks (Vinaya: Pac.10, 11).
*Animals are clearly part of samsara and face rebirth (numerous past life jataka stories, reports of people with past lives as animals).
*The five aggregates (skandhas) form, sensations, perceptions, mental formations, consciousness
So according to Buddhism for the living things on earth, we could say humans and all animals that possess the five aggregates, especially consciousness, i.e., some level or degree of self-awareness (as most likely being the determinate factor).