18 Aug 2018 12:17 AM EST

Airlines have increasingly struggled with the growing numbers of passengers trying to travel with service or emotional support animals. Southwest Airlines has made a formal policy saying they won't allow insects, spiders, rabbits, ferrets, or rodents to travel with passengers. The airline will, however, continue to allow dogs and cats as service animals, and starting next month, they will also allow trained miniature horses on board. Miniature horses are recognized as a service animal by the Americans with Disabilities Act, which oversees laws about service animals. They are stronger and live longer than most service dogs.