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Humans selectively bred dogs thousands of years ago to achieve the perfect “puppy dog eyes,” according to a new study.
The scientists behind the study say that a dog’s adoring and pleading expression, known as puppy dog eyes, has been bred into canines to give them more human-like faces. This trait to form facial expressions was likely achieved through thousands of years of selective breeding.
“Throughout the domestication process, humans may have bred dogs selectively based on facial expressions that were similar to their own, and over time dog muscles could have evolved to become ‘faster,’ further benefiting communication between dogs and humans,” Professor Anne Burrows of Duquesne University in Pittsburgh told SWNS.
Muscle cells with more “slow-twitch” fibers are more efficient, creating controlled movements that don’t tire as quickly.
For the study, researchers compared the myosin fibers in facial muscle samples from wolves and domesticated dogs.
More fast-twitch fibers allow greater facial mobility and faster muscle movement, enabling small movements such as a raised eyebrow, puppy dog eyes, and the short, powerful muscle contractions involved in barking.
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Slow-twitch fibers, on the other hand, are important for extended muscle movements such as those wolves use when howling.
Dogs also have an additional muscle absent in wolves which contributes to the “puppy-dog eye” expression.
“Dogs are unique from other mammals in their reciprocated bond with humans, which can be demonstrated through mutual gaze, something we do not observe between humans and other domesticated mammals such as horses or cats,” Burrows said.
“Our preliminary findings provide a deeper understanding of the role facial expressions play in dog-human interactions and communication,” she added. “These differences suggest that having faster muscle fibers contributes to a dog’s ability to communicate effectively with people.”
This research was presented at an annual meeting of the American Association for Anatomy.
source: people.com
