Study: Docile Raccoons are Trash Can Criminal Masterminds

Study: Docile Raccoons are Trash Can Criminal Masterminds

Researchers have assessed the habituation, learning and cognitive flexibility of a wild population of raccoons (Procyon lotor) in Wyoming, the United States.

Raccoons are medium-sized carnivores that demonstrate incredible success in novel and urban environments yet have been understudied within the fields of animal behavior and cognition.

Their native range in North America is currently expanding, and raccoons are now in many parts of Europe and Asia owing to human-mediated introductions.

Historical records of raccoon behavior and distribution suggest that raccoon exploitation of urban areas has been longstanding, and these animals are commonly found in high densities in North American cities today.

Although their cognition has been generally underexplored, raccoons are well known for their intelligence and innovative foraging strategies.

“We used live traps baited with cat food to humanely capture raccoons living in the city of Laramie, Wyoming,” said Dr. Lauren Stanton, a researcher in the Department of Environmental Science, Policy, and Management at the University of California, Berkeley.

Dr. Stanton and her colleagues then transported the animals to the lab to assess their health and how feisty or docile they were.

They injected tiny radio frequency ID tags between the animals’ shoulder blades to individually identify them before returning the animals to their home territories, keeping track of their impulsivity by recording each time an individual ended up in a trap again.

Between August 2015 and September 2019, the researchers tagged a total of 204 wild raccoons.

They tested how well the raccoons learned and adapted to change by locating a raccoon-sized cubicle in the animals’ neighborhood, equipped with two buttons: one that released a handful of tasty dog food treats when pressed, and a second one that provided nothing.

However, once each raccoon had overcome its misgivings and learned to climb inside the cubicle and obtain its edible reward, the authors turned the tables on the animals, switching which button dispensed the dog food reward, to find out how quickly the raccoons figured out the change.

However, the scientists admit that they hadn’t factored in how popular the raccoon cubicle would be, with several animals often trying to crowd inside simultaneously, bumping and distracting the raccoon at the console as it tried to obtain its dog food treat.

After two patient years, 27 raccoons got the hang of visiting the cubicle, with 19 figuring out how to press the buttons to provide themselves with rewards, and 17 realizing that they had to depress the other button when the team tried to outfox them.

Initially, the youngest raccoons seemed the keenest to explore the experimental cubicle; however, the adults were better prepared for adversity when the researchers switched the console buttons.

“And when we checked the animals’ temperaments, the least bold and most docile raccoons seemed best prepared to learn how to operate the console, which suggests a potential relationship between emotional reactivity and cognitive ability in raccoons,” Dr. Stanton said.

“However, when we compared how the raccoons in the Laramie suburbs coped, compared with the wild raccoons that tried out their paws in a peaceful lab, the captive animals seemed to pick up the test more readily, likely because there were more distractions and interruptions during testing in the natural conditions.”

The findings were published in the Journal of Experimental Biology.


Lauren A. Stanton et al. 2022. Environmental, individual and social traits of free-ranging raccoons influence performance in cognitive testing. J Exp Biol 225 (18): jeb243726; doi: 10.1242/jeb.243726

This article was first published by Sci News on 26 September 2022. Lead Image: Raccoons (Procyon lotor). Image credit: Daniel Steinke.

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