Urban raccoons are showing early signs of domestication, a new study finds.
Using photos uploaded to citizen science platform iNaturalist, researchers found that raccoons in urban environments have shorter snouts than their rural counterparts. The difference may be one of several traits that make up the “domestication syndrome,” the scientists wrote in a study published Oct. 2 in the journal. Frontiers in Zoology.
“I wanted to know whether living in an urban environment would trigger domestication processes in animals that are not currently domesticated,” study co-author. Rafaela LeshThis was stated by a zoologist from the University of Arkansas at Little Rock. statement. “Will raccoons be on the path to domestication simply by being in close proximity to humans?”
Domestication begins when animals adapt to a new niche created by human presence. For raccoons, that niche may involve digging in our trash cans.
“Trash is actually a kickstarter,” Lesh said. This waste becomes easy prey for the creatures. “All they have to do is tolerate our presence, not be aggressive, and then they can feast on everything we throw out.”
In the new study, Lesch and a team of 16 students looked for early signs of raccoon domestication in the United States. Physical signs that a species is becoming domesticated often include a shorter snout, floppy ears, white patches, and a decreased fear response—a set of signs that are collectively referred to as “domestication syndrome.”
Drawing from nearly 20,000 photos uploaded to iNaturalistthe team found that the snouts of raccoons living in densely populated areas were about 3.5% shorter than those of raccoons in more rural counties.
These seemingly unrelated features of the “domestication syndrome” typically occur during the early stages of domestication and may be related to mutations that occur during the animal's development. In 2014, scientists suggested that mutations in neural crest cellsa type of stem cell produced in vertebrate embryos may cause these changes.
The new findings appear to support this hypothesis, the researchers wrote in the study. Reducing the fear response helps animals like raccoons take advantage of their human surroundings, so natural selection may make this bravery more common in urban environments. According to the team, changes in snout length early in domestication may indicate that the two traits are related.
Future studies will examine whether the same pattern holds true for other urban mammals, such as opossums, according to the statement.
“This will help us know whether human presence is enough to already begin the process of domesticating a species,” Lesh said.
