It's important that their costumes don't have too many small parts.

Washington - We know that you and your friends will probably be dressing up this Halloween, but what about your pets? 

Maybe your pet already rocks a sweater in the cold, but most animals aren't used to wearing clothing or accessories. So how to keep your furry friend festive but also safe and comfortable?

It's important that their costumes don't have too many small parts, such as buttons or strings, that they could eat, said Lori Bierbrier, director for community medicine for the American Society for the Prevention of Cruelty to Animals. 

Your cats or dogs won't know the difference between their costume and their chew toys, so an adult should supervise dress-up time. An adult who can watch for signs of distress should put the costume on the pet as well.

"Look for something the least intrusive," Bierbrier said. Something that covers the face, such as a mask or an oversize hat, is a bad idea because it could prevent your pet from seeing, breathing or eating, she added.

A sign that it's time to take off the costume is changes in your pet's behavior. If they're growling, scratching themselves a lot or hiding, it's a sure sign that they aren't enjoying the costume. Some animals like to dress up, but others don't, so keep them in costume only for as long as they seem happy.

If you have your heart set on trick-or-treating with your dog, Bierbrier recommends getting him or her used to the costume ahead of time. Dress up your pup a few weeks before Halloween for short amounts of time, offering rewards so that the dog sees the costume as a good thing and not a sudden, unpleasant surprise. Otherwise, it might feel like you're giving your pet a treat, but they probably won't find it as sweet.