14 CFR Part 382 Nondiscrimination on the Basis of Disability in Air Travel (Air Carrier Access Act): Preamble and Section-by-Section Analysis (with amendments issued through July 2010)
What about unusual service animals?
As indicated above, certain unusual service animals, (e.g., snakes, other reptiles, ferrets, rodents, and spiders) pose unavoidable safety and/or public health concerns and airlines are not required to transport them. The release of such an animal in the aircraft cabin could result in a direct threat to the health or safety of passengers and crewmembers. For these reasons, airlines are not required to transport these types of service animals in the cabin, and carriage in the cargo hold will be in accordance with company policies on the carriage of animals generally.
Other unusual animals such as miniature horses, pigs, and monkeys should be evaluated on a case-by-case basis by U.S. carriers. Factors to consider are the animal’s size, weight, state and foreign country restrictions, and whether or not the animal would pose a direct threat to the health or safety of others, or cause a fundamental alteration (e.g., significant disruption) in the cabin service. If none of these factors apply, the animal may accompany the passenger in the cabin. In most other situations, the animal should be carried in the cargo hold in accordance with company policy. Under the 2008 final rule, foreign carriers are not required to transport animals other than dogs.