Urban raccoons display initial signs of domestication when living close to humans

The clever raccoon rummaging through city garbage might represent more than just a backyard annoyanceit could illustrate evolution happening in real time. Recent research indicates that raccoons living in human-populated areas are showing physical traits associated with the initial phases of domestication, similar to the ancestors of domestic dogs and cats.

The study, recently published in Frontiers in Zoology, examined nearly 20,000 images of raccoons from across the continental United States. Led by Raffaela Lesch of the University of Arkansas at Little Rock, the team discovered a notable distinction: raccoons residing in urban environments have shorter snouts compared to their rural counterparts.

Shortened snouts are a hallmark of "domestication syndrome," a suite of physical changes that includes altered coat patterns, smaller teeth, ear and tail modifications, and craniofacial shifts. These traits tend to appear as animals become more docile, tolerant, and less aggressive toward humans.

Lesch sought to determine whether simply living near human settlements could trigger such changes in wild animals. Her findings suggest that it can, with human food waste playing a central role. "Animals are drawn to our garbage. Its an easy meal. If they can tolerate our presence without being aggressive, they gain access to abundant food," she explained.

In cities, raccoons that are calmer and less fearful of humans have a competitive advantage in reaching trash cans, the easiest food source. Over time, the preference for tameness appears to influence facial and snout morphology, consistent with the neural crest domestication syndrome hypothesis.

Lesch remarked with humor, "It would be fitting if raccoons became our next domesticated species. Perhaps we could call the tamer version the 'trash panda.'"

The study also highlighted the contributions of students, with 16 college and graduate researchers listed as co-authors.

The team is now validating their photo-based measurements using 3D scans of raccoon skulls from the university collection. They are also expanding the project to examine other urban mammals, such as armadillos and opossums, to determine if similar evolutionary changes are occurring.

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Author: Sophia Brooks