North American House Hippo.

I'm not sure if it's specifically illegal to own a deer as a pet (probably varies by state/country law), but it wouldn't be a good idea, at least for the deer. As wild prey animals, deer are generally scared of humans (a trait that is hard-wired into their DNA and unfortunately cannot be fixed through kindness, love, and care). Deer also notoriously carry ticks that are harmful to humans. Now, it is possible that they could be *actually* domesticated--that is, the process of selective breeding to phase out undesirable traits (like fear of humans, aggression, etc). When people call animals "domestic", it usually doesn't just mean an animal that is kept as a pet; it means the animal has been selectively bred by people. Domestication of a species requires a lot of time and resources to breed the wild animal for traits that would make it more suitable for life as a human companion. This is what humans did with dogs however many centuries ago (after all, people don't/shouldn't keep wolves as pets because they are wild animals). Now, in general, the animals that humans have chosen to domesticate in this way have 1. Been done a long time ago and 2. had a reason to be tamed. Cows were raised for their meat, milk, and labor, horses were tamed to ride, wolves for their hunting skills. Unfortunately, it's likely deer in general aren't widely domesticated (reindeer are the only ones I know of) because other animals have done what they could do better (less meat than cows, not as strong as horses, etc.) I suppose cuteness factor isn't typically enough reason to domesticate an animal, although a scientist in the 1960's I want to say? Successfully ran an experiment to domesticate silver foxes. So theoretically if someone dedicated, smart, and/or rich enough really wanted to, they could run a deer domestication program of their own. I don't know if it would be successful, though. Until then we will just have to admire these cute guys from a distance.

@@chocoboko123 Thanks . Excellent reasoning. I was thinking that someday these creatures will vanish unless preserved. One way to do it is to allow domestication.