If the beavers banded together and tried to exterminate humanity, they wouldn’t get as far as humanity would exterminating beaverkind. That’s domination: exerting your will on those around you to their detriment and not being deterred by their resistance, no?

I don’t think that’s a fun competition or nice thing to consider, but there are few animals that could come close to beating us in that regard. Ants, termites, and bees are the first that come to mind for me, but there are probably other possibilities.

Plants, fungi, and bacteria on the other hand… I don’t think we could really expect to win against the most ubiquitous examples of those.