WASHINGTON, Dec 2 (Reuters) - Only trained dogs qualify as service animals on U.S. airlines, as regulators rejected requests to extend legal protections to miniature horses, monkeys and other species, under final U.S. Transportation Department rules issued Wednesday.

Airlines can still choose which other species to allow onboard, but the rules issued on Wednesday largely resolve years of disputes with passengers who falsely claim pets as emotional support animals, which may travel in the cabin with little oversight.

Under existing rules, airlines were required to recognize with limited exceptions emotional support animals as service animals. Now they can classify them as pets.

Legally protected service animals are now limited to dogs trained to do perform tasks for a person who may be visually impaired or have psychiatric or other disabilities, and airlines do not have to allow emotional support animals.