Humans are basically the only mammal that eats capsaicin
I had a dog who liked pepper sauce.
Story time: I was 14 or so. Eating fish patties. As usual, drowning them in pepper sauce. Lana (my dog, a mid-large poodle) kept nagging me for food, it was annoying. I offered her a tiny bit of the patty, with pepper sauce. I expected her to smell it and think “eeew, humans eat this? Human food is inedible!”. Instead she ate it, licked the floor, and asked me more.