Animals of all life forms are the best pets. Because humans are animals, we relate better to other animals, especially other mammals. We are also the best caretakers for domesticated animals such as cats, dogs and goats. It is a mutually beneficial relationship that helps the human and the pet live longer and happier lives.
Take animals into captivity is like taking humans from a 3rd world country and putting them into a 1st world country. There, they don't have to hunt for food, find clean water, and find shelter. Animals tend to live longer in captivity, so it must be better for them to be in captivity.
Cats, dogs, domestic rodents such as hamsters and ferrets, these are all housed in your house and my house. Would you rather they run free in the streets with no natural predator to keep their numbers down? Domesticating and having certain animals as pets is much more humane than the alternative.