Exotic pets are becoming popular for a number of reasons. First of all, they can be rare and not as common as dogs or cats. Any animal that isn't domesticated can be considered an exotic animal. This is a list of some of the most exotic pets in the US.
15,000 non-human primates are kept by private individuals as pets in the US. But as a species, they're very high-maintenance. They need a lot of attention! They also require regular visits to the vet, because they need to be vaccinated against many risky diseases. Many professionals, including vets, zoologists, humane societies and others, strongly discourage the keeping of non-human primates as pets, as their complex emotional and social needs and other highly specialized requirements may be difficult (but not impossible) to meet by the average owner.