Analogizing animal behavior to human motivations feels intuitive but requires really big assumptions which scientists know they can't really defend, so they just have to avoid that topic.
Mine go the opposite way: I assume that when I see a dog or a cat or a rat or a ferret or a pig (all with brain and body structure completely analogous to my own) show an emotion or performing an act I can immediately relate to, their internal state is fairly much as my own would be in similar circumstances.
Claiming myself and my kin to be qualitatively entirely different from every other living species, now that is an assumption I wouldn't be comfortable to make.