Why Dogs Curl Up Into a Ball Before Going to Sleep

Repost from Vetstreet.com August 22, 2012

By Rae Paoletta

There is no better evening spent than on the couch with your dog. Their warm little bodies and sweet personalities make them the best cuddle buddies ever. It’s no wonder that we will often prefer spending time with our dogs than with other people. But have you ever noticed that when your dog decides to curl up beside you, they often contort themselves into tight little balls of fur? They’ll sometimes do a circle or two around the sofa before they plant themselves on the couch and curl up into the adorable little balls that we love to photograph. And while most of us probably see it as them getting comfortable, there is actually more behind it than just comfort. 

As Dr. Margaret Gruen, an assistant professor of Behavioral Medicine with NC State University’s College of Veterinary Medicine, explained, dogs’ actions of curling up is an evolutionary behavior that has long been rooted in their DNA. It has to do with outside temperatures. As she explained, back when our dogs were wild and slept outdoors, they would often dig themselves a little nest for warmth and then curl up into it. This action of packing themselves tightly into a little ball – while obviously adorable – was very much a survival tactic. It was a way for them to conserve their body heat. 

In addition, sleeping outdoors can sometimes come with dangers. For anyone who has gone camping, there are sometimes bigger and scarier things out there in the wild during the nighttime hours. For any sleeping dogs, curling up in a ball was a way for them to try to protect their most vital organs in their abdomens from a potential attack while asleep. While it may seem silly or even paranoid to us that our dogs are still trying to protect themselves while they sleep, it is all a remnant of their wild past.  

And while they may live in a loving home where they have no need to fear for their safety, it’s something evolutionary that will never leave them. But at least this quirky little habit of theirs makes for some pretty darn cute social media posts! Who else loves to take pictures of their dogs while they sleep?