A troubling practice called “dog flipping” is on the rise in many parts of the U.S. Dog flipping is when a family dog is stolen from its owners and then turned around and sold online, such as on Craigslist, for a profit.

The American Kennel Club reports that dog flipping statistics have been on the rise since 2008, when it began keeping statistics. In 2008, the AKC recorded 71 dog thefts, but in 2014, the number rose to 637. Actual numbers are probably much higher.

Dog flipping is a traumatic experience for both dogs and owners. Dogs are taken away from their homes and families and are passed on to strangers. While some owners will never see their dogs again, others have reported seeing online ads for their own stolen pets.

The most common dog breeds that are stolen are pit bulls and pit bull mixes, followed by Yorkies, Chihuahuas, bulldogs, Pomeranians, Shih Tzus, and German shepherds. Dog flippers will either steal a family pet or claim to be the owner of a lost pet. Once they have the dog, they will then sell it online for hundreds of dollars.

What can you do to help keep your dog safe? Always keep your dog leashed and close to you when you are out. Never leave your dog unattended in public places or even in your own backyard. Be sure to have your dog microchipped and keep all information with the microchip service up to date. Don’t tell strangers who approach you on the street or in the park and ask you how much your dog costs.