Unusual pets are fairly commons sights at the airport these days, but due to recent crackdowns, not all of them make it past the security gate. Many airlines try to limit the animals they allow in their cabin to cats and dogs, but following new guidelines issued by the U.S. Department of Transportation, that list may soon get more diverse. As The Drive reports, the DoT is now encouraging airlines to accept miniature horses as legitimate service animals for flyers.

Commercial airplanes, which aren't exactly known for being spacious, may be the last places you'd expect to see a horse. But miniature horses can provide essential services to people with disabilities such as visual impairments or mobility issues. Even though they're not very common as household pets, miniature horses rank among cats and dogs as some the most popular service animals.

With this in mind, the DoT updated its guidelines on which species should be permitted to fly in the cabins of commercial planes. The statement [PDF] reads:

"[A]fter reviewing the comments on this issue, we believe that it would be in the public interest and within our discretionary authority to prioritize ensuring that the most commonly recognized service animals (i.e., dogs, cats, and miniature horses) are accepted for transport."

This doesn't mean that all airlines are now obligated to board therapy mini horses by law, but if they decide to ignore the new guideline, they could face a penalty. The document also doesn't say that every service animal that isn't a cat, dog, or mini horse should be rejected outright; rather, every animal that's brought to an airline—whether it's a pig or peacock—should be considered on a case-by-case basis. The only creatures commercial flight companies are allowed to ban explicitly from flying with passengers are ferrets, rodents, snakes, reptiles, and spiders.

It's worth noting that the new guidelines don't necessarily apply to emotional support horses; while service animals are trained and protected by the Americans with Disabilities Act, emotional support animals require no training, just the assertion from their owners (and often a letter from a doctor) that the pet provides essential comfort. For this reason, emotional support animals are much more difficult to get into the cabins of planes.

[h/t The Drive]