Why can't so many animals vomit? I keep hearing triva quotes of "rats cannot vomit", or "horses cannot vomit", or "frogs cannot vomit" and the question is, why? Won't it be a very useful evolutionary adaptation to be able to eject ingested toxins or irritants?
there's plenty of reasons that many other animals can't vomit! the act of vomiting is actually fairly complicated biologically speaking, and requires:
a) a neurological path to detect unwanted material and trigger the rest of the physical process of vomiting, which needs
b) a reversible entry between the esophagus and stomach, and
c) a diaphragm muscle powerful enough to contract the entire midtorso hard enough to empty the stomach violently backwards up the esophagus without accidentally getting anything into the lungs (this is why vomiting kind of feels like you're dying)
animals that don't have access to the vomit ability tree for lack of any of these systems tend to just have really REALLY beefy digestive processes that can break down most harmful things they could reasonably eat by mistake, or else they do something else entirely to purge their system.
for example! frogs cannot vomit, true. but they CAN just evert their entire stomach inside-out out of their mouths, scrape the offending insect off with their little frog paws, and slurp it back down into their torso!
yeah, humans definitely got the winning deal here, I'm going to be honest.
