Basset Hounds, Bloodhounds, Beagles—there are countless dog breeds best known for their adorable floppy ears. Big droopy ears that flop back and forth and flutter in the wind make for a cute pup, and science has a theory about why so many dog breeds have the distinctive trait. For their explanation, researchers first look to the wild. Dogs were domesticated from wolves, but comparing them now, few dog breeds have actual physical similarities to their wild ancestors—ears included.
You could search for years, but you won’t find a wolf with a pair of floppy ears perched on its head. When humans first started interacting with wolves, they introduced selective breeding. ABC News reports generations of breeding dogs for specific qualities has lead to unexpected repercussions. Humans have bred dogs based on appearance, athleticism, instinct, and several other factors. They’ve created breeds that are good at herding and hunting, and they’ve also altered breeds to make their backs longer, snouts shorter, and muscles bigger. And behind all those intended purposes, there were changes they never expected. Vet Organics calls it a “universal malfunction in the majority of dog breeds” and Charles Darwin called it “domestication syndrome.”
The theory suggests that while humans were dabbling in genetic engineering by pairing specific dogs in order to produce puppies with specific qualities, there was a change in stem cells. Adam Wilkins from the Institute of Theoretical Biology in Berlin said in an article with ABC News,
“The history of breeding is rich in this sort of thing, you breed selectively for one trait and often get something unexpected that is linked to it in some unanticipated way.”
When comparing today’s domesticated dog with their wolf ancestors, evidence shows several physical differences that could be a result of this domestication syndrome. Dogs have shorter muzzles, smaller jaws, smaller brains, less adrenaline, and—you guessed it—floppy ears.
Scientists believe that somewhere down the line, canine embryonic development started to change. Stem cells started to malfunction for an unknown reason. Cells that were supposed to contribute to ear structure never made it to the top of the head, or if they did, they arrived in a weak condition. The result is a “deformed” ear that doesn’t stand up on its own. Continued breeding passed the trait on through generations of dogs, and now it’s a regular occurrence.
If this theory holds true, floppy ears are technically a defect. Unlike other deformities caused by breeding (ruptured spinal discs in Dachshunds and flattened snouts in Boxers) floppy ears have few (if any) negative consequences. The biggest worry for dogs with floppy ears is keeping them clean.
Floppy ears in dogs is now the norm. Even breeds thought of being highly alert have floppy ears. Dobermans, Pit Bulls, and German Shepherd are all generally pictured with pointy ears, but it’s not uncommon for individual dogs to have droopy ears.
Science says floppy ears are a defect caused by domestication, but every dog owner knows floppy ears are another reason why they love their four-legged best friends. But no matter how cute the dog is, their ears are a sign that even the smartest scientists and the best breeders can’t predict the unintended effects of domestication and selective breeding. Researchers say there’s a chance the continuation of selective breeding will lead to additional “defects.”
If that does happen, the results might not be as cute and harmless as floppy ears.