Humans selectively bred canines to give them irresistible ‘puppy-dog eyes’, scientists say

The best of Voices delivered to your inbox every week - from controversial columns to expert analysis Sign up for our free weekly Voices newsletter for expert opinion and columns Sign up to our free weekly Voices newsletter Please enter a valid email address Please enter a valid email address SIGN UP I would like to be emailed about offers, events and updates from The Independent. Please try again later {{ /verifyErrors }} The irresistible “puppy-dog eyes” expression formed by dogs may have been the result of selective canine breeding by humans, suggests new research. Researchers, including Anne Burrows from Duquesne University in Pittsburgh, said these muscles are dominated by “fast-twitch” myosin fibres in humans that contract quickly but also fatigue quickly, explaining why people can form facial expressions rapidly, but not hold them for long. “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,” she added. Having more fast-twitch fibres allows dogs greater facial mobility and faster muscle movement, enabling small movements such as a raised eyebrow and the short, powerful muscle contractions involved in barking, scientists explained.