I believe it's been shown as a general capability in [corvids](https://www.semanticscholar.org/paper/Ravens-attribute-visual-access-to-unseen-Bugnyar-Reber/228a

I believe it's been shown as a general capability in [corvids](https://www.semanticscholar.org/paper/Ravens-attribute-visual-access-to-unseen-Bugnyar-Reber/228a4cd7ac54275cbd3f4fa1db73f85d742462e7 https://www.semanticscholar.org/paper/Ravens-attribute-visua...), great apes and maybe possibly in pigs (and goats). It's sort of game theoretic, as in "I know that you know that I stash food here so I'm going to pretend to hide the food here". I've never read anything that goes beyond two levels of "I knows" but it can be sophisticated, such as in the linked paper on Ravens where there is line of sight through a peephole that can be open or closed. Sophisticated ToM is likely rare in the animal kingdom, not usually going beyond programmed responses to being observed and possibly empathizing with conspecific suffering. In humans, it's a much more sophisticated process of inferring motivations, anticipating moves and a number of similar inferential capabilities plus abductive reasoning.