No. Bed bugs are also pests in poultry operations, and they're known to parasitize bats. Some labs that study bed bugs rear them on guinea pigs and mice. The bugs might feed on cats and dogs. Fur is probably a barrier to them, but they could feed at any place on the body without fur. Bed bugs are not specific to humans, but they are adapted to parasitizing us.

The size of bed bug bites varies with a number of different factors. Bed bugs inject an anti-coagulant along with their saliva when they pierce the skin to take a blood meal. This anti-coagulant is mostly responsible for how a person reacts to the bite and determines the size of the bug’s bite. Since people will have various sensitivities to the bed bug’s bite, the size of the bite will vary, as well. Another factor that influences the size of a bed bug reaction is the number of times a person is bitten. Bite reactions of people bitten many times are also variable, and their response may be either more or less intense as the number of bites increases.