For years, scientists have thought that the irresistible, wide-eyed expression known as “puppy dog eyes” was something only domestic dogs had mastered. We were sure the look evolved to tug at human heartstrings. But now, a surprising discovery is turning that idea on its head: Coyotes, too, can pull off this familiar gaze.
New research from Baylor University reveals that coyotes, like dogs, have the facial muscles necessary to create this captivating expression. Rather than being a feature that only evolved during domestication, the new findings suggest instead that “puppy dog eyes” might be a much older trait — one that wild canids have carried for far longer than we imagined.
It turns out, the emotional power of those sad, raised eyebrows might not be all about us after all.
A Closer Look at Coyotes
The study, led by Ph.D. student Patrick Cunningham, examined the facial muscles of 10 coyotes from Texas. What he and colleagues found was striking and unexpected. Just like domestic dogs, these wild animals possess a well-developed muscle called the levator anguli oculi medialis (LAOM). This small muscle is responsible for raising the inner eyebrow, producing that familiar, pleading look.
Coyotes, it seems, have had the capacity to make this expression all along.
“Our findings suggest that the ability to produce ‘puppy dog eyes’ is not a unique product of dog domestication,” Cunningham said. “It’s an ancestral trait shared by multiple species in the Canis genus.”
“This raises fascinating questions about the role of facial expressions in communication and survival among wild canids,” he added.
Superficial coyote facial expression muscles are shown in dorsal (a) and lateral (b) view. Deep facial expression muscles are shown in lateral view (c) Fibre directions are shown in white. Dashed lines indicate a deeper muscle. Note the well-developed levator anguli oculi medialis and retractor anguli oculi lateralis, and the faint medial fibres of the frontalis. Credit: Royal Society Publishing.
For decades, the prevailing notion has been that dogs developed this facial feature as they evolved alongside humans. Likely humans favored dogs that could communicate through expressive faces. Furthermore, studies have shown that gray wolves, dogs’ closest living relatives, don’t have the same developed LAOM muscle. Naturally this lead to the theory that humans played a role in its evolution.
This was also confirmed by the new study. When the researchers compared coyotes and dogs to gray wolves, they found that while dogs and coyotes have the eyebrow-raising muscle, gray wolves do not. This suggests that the LAOM muscle was at one point present in the common ancestor of dogs, coyotes, and wolves but the latter lost the trait somewhere along the evolutionary line.
So, while all this time scientists thought that dogs were special, it turns out that wolves are the unique species.
Ancient Expression, Modern Questions
The study’s findings don’t just raise eyebrows — they raise questions, too. If wild coyotes can make “puppy dog eyes,” what role does this expression play in their world? Unlike domestic dogs, coyotes don’t need to charm humans for survival. Could these facial muscles be used for communication between coyotes in the wild?
Researchers still don’t know for sure. While Cunningham has seen photos of coyotes seemingly making the expression, he cautions that there’s no hard evidence yet that they use it in social interactions.
This discovery also forces scientists to rethink the broader role of facial expressions in canid evolution. Early hypotheses suggested that the LAOM muscle might have originally evolved for more basic functions, such as improving vision or eye movements. But now, it appears that many wild canids — including African wild dogs — also possess these eyebrow-raising muscles. This hints that the expression could be an ancient trait passed down through generations of wild canids.
Phylogeny that show the relationship of the four canid species in which the levator anguli oculi medialis (LAOM) has been studied. Credit: Royal Society Publishing.
Red wolves, golden jackals, and other distant relatives of dogs may also have the ability to make the same expression. If so, the “puppy dog eyes” trait could be far more widespread in the animal kingdom than anyone previously thought.
More Intriguing Things to Study
Still, even without a clear answer on how coyotes use this expression, the implications for dog domestication are intriguing. Dogs, after all, have spent thousands of years by our sides, using their expressive faces to communicate with us in ways that seem almost intuitive. In fact, a 2013 study found that dogs in shelters who frequently raised their inner eyebrows were adopted more quickly than those who didn’t.
Could the same dynamic have been at work thousands of years ago, when humans first began to cozy up to dogs? Did their ancestral “puppy eyes” seduce us?
“We don’t really know how to fit all the pieces together yet,” Burrows told Science. “But we know that something was going on in the early days of dog domestication that involved eye gaze.”
The sad, soulful gaze we thought was designed just for us might, in fact, be a shared language — one much older than our bond with dogs. And that’s a look worth considering.
