Recent research suggests that a muscle called the levator medial oculi (LAOM) is unique to dogs (canine) and evolved through domestication. This muscle lifts the inner eyebrows, creating a “puppy eye” look. In a new study, Baylor University scientists tested whether LAOM is a derived trait in dogs by (i) examining facial muscles in closely related wild ancestors; canis seed, Coyote (canis latrans) (ii) compare your results with other results; canis and canine species. They discovered that coyotes, like dogs, have well-developed LAOMs. This is different from the modified/absent LAOM of gray wolves. Their findings cast doubt on the hypothesis that LAOM developed through domestication.
Like dogs, coyotes have a well-developed LAOM, which gives both species the ability to develop “puppy eyes.” Image credit: Cunningham others., doi: 10.1098/rsos.241046.
“Our findings suggest that the ability to produce 'puppy eyes' is not a unique product of dog domestication, but rather an ancestral trait shared by multiple species on Earth. . canis genus,” said Dr. Patrick Cunningham. student at Baylor University.
“This raises interesting questions about the role of facial expressions in communication and survival in wild canids.”
In this study, Cunningham and colleagues compared the facial muscles of coyotes, dogs, and gray wolves.
Both dogs and coyotes have well-developed LAOMs, but gray wolves' muscles are modified or absent.
This challenges the hypothesis that human-driven selection alone is responsible for the development of the inner eyebrow ridge in dogs.
Instead, this study suggests that LAOM was likely present in the common ancestor of dogs, coyotes and gray wolves, but was later lost or reduced in wolves.
The researchers also documented significant within-species variation in coyote facial muscles, particularly those related to eyebrow and lip movements.
Genetic analysis excluded significant canine ancestry in the coyote specimen, confirming that these traits were not the result of interbreeding.
“Our research shows that coyotes and dogs not only share behavioral similarities, but also an interesting evolutionary history, including the ability to make expressions that were once thought to be unique to domestic animals. “We made it clear,” Cunningham said.
“This discovery has broader implications for understanding the evolution of facial expressions in mammals.”
“LAOM may have originally evolved for functions related to vision and eye movements, rather than for human communication, as previously thought.”
“Future studies on other canid species, such as red wolves and African wild dogs, may further elucidate the role of facial expressions in survival and species communication.”
a paper The survey results were published in a magazine Royal Society Open Science.
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Patrick Cunningham others. 2024. Coyotes can also have “puppy eyes”: a comparison of interspecific variation. canis Facial muscles. R. Soc. Open Science 11(10):241046;doi: 10.1098/rsos.241046
Source: www.sci.news
