Dogs — check. Cats — check. A miniature horse? Maybe. Peacocks, pigs, or monkeys? Sorry. Starting Monday, Alaska Airlines will enforce new rules for emotional support animals and service animals on its flights.

And yes, miniature horses count as a service animal on Alaska Airlines flights.

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It’s the latest airline to implement such rules after a variety of emotional support animals have shown up on flights, stirring the emotions of other passengers. Such emotionally-supportive animals have included turkeys, a kangaroo, and a duck named Mr. Daniel Turducken Stinkerbutt. But airlines are cracking down on which animals they will allow on flights — basically, dogs and cats.

One important note: There are two categories of animals according to Alaska Airlines. There are service animals, and emotional support animals. Service animals help people with physical disabilities, such as vision or hearing impairment. Emotional support animals aid people with mental health-related disabilities.

Miniatures horses are only allowed as service animals, not emotional support animals. If miniature Mr. Ed helps guide blind passengers on the plane, then that is OK. If he is just there as your buddy, he’s not allowed in the passenger cabin.

Starting Monday, Oct. 1 — regardless of when a flight was booked — Alaska’s new animal guidelines go into effect:

Passengers may bring only one emotional support animal on a flight.

Such animals are limited to dogs and cats. No other species allowed.

Pets must be in a carrier or leashed at all times.

Passengers must provide 48 hour notice they are taking the pet with them.

Passengers must provide documentation that their pet is an emotional support animal.

Service animals (includes psychiatric service animals) limited to either a dog, cat, or miniature horse.

The airline industry estimated that there was a 57 percent increase in the number of emotional support animals on flights between 2016 and 2017 — growing from 481,000 to 751,000, according to ABC News. United Airlines alone saw a 75 percent increase in emotional support animals in that one year.

Delta Airlines has also banned pit bulls on its flights.