Horses and dogs share a surprisingly common language of play
Dogs and horses are evolutionarily enemies, but domestication has allowed them to have a peaceful co-existence.
By Virginia Morell
April 16, 2020
A dog’s invitation to play is unmistakable: Bowing with his front legs and wagging his tail, he’s basically saying to another dog, Let’s have fun! The two animals then chase and leap and box each other, matching each other’s moves, often with expressions we humans interpret as smiles.
Now scientists report for the first time that dogs and horses play together in a similar manner, with open mouths and synchronously matched behaviors.
Perhaps most remarkably, the two species also rapidly mirror the expression on the other’s face, a behavior called rapid facial mimicry. This phenomenon occurs in primates, domestic dogs, meerkats, and sun bears, but has never been documented between play partners of different species.
“It’s a wonderful study, and takes the questions surrounding play behavior to a new level,” says Sue McDonnell, an animal behaviorist at the University of Pennsylvania in Philadelphia who wasn’t involved in the study.
“In particular, they’ve beautifully demonstrated play between two species where it’s unexpected."”
Horses and dogs coexist peacefully today thanks to centuries of domestication. Still, from an evolutionary point of view, they're predators and prey, so scientists were surprised the two species shared a common language of play.
What’s more, the study strengthens the idea that play is universal among species. The behavior occurs in such a wide array of creatures—ranging from crocodiles to otters to wasps—that scientists believe it has evolved multiple times. Despite these diverse origins, play behaviors—play-fighting, running, chasing, leaping—are strikingly similar across nature.
The purpose behind play is murkier. It could help young animals develop social and hunting skills; adults may use it to relax or maintain their health. The new study, between such different animals, adds an intriguing new element to the mystery.