American Airlines is setting some new ground rules on emotional support animals , barring companions like spiders, hedgehogs, goats and snakes from taking flight.

The airline unveiled a list of prohibited animals on Monday after it said a growing number of passengers have taken or attempted to take a range of animals on board planes for emotional support including a peacock , pig and hamster on other airlines.

From 2016 to 2017, the airline said it saw a 40 percent rise in service or support animals on its aircraft similar to increases at other airlines like Delta and United, which made similar changes this year.

At American, we want to have policies and procedures in place that protect our team members and our customers who have a real need for a trained service or support animal, American said in a statement.