How People Make Some Squirrels Better Problem Solvers

Squirrels can be better (or worse) at solving puzzles in the city, study finds.

A Eurasian red squirrel and the puzzle box in Tsuda Park at Obihiro, Japan
A Eurasian red squirrel and the puzzle box in Tsuda Park at Obihiro, Japan.

Pizza Ka Yee Chow

Having humans around isn’t always great for wildlife. Urban areas typically have more people and buildings and less tree cover and habitat, making city life challenging for animals.

Some squirrels have trouble problem solving when surrounded by all these human disturbances. Other squirrels, however, are able to adapt their behavior and thrive, new research finds.

For the study, a team of researchers created challenges for wild Eurasian red squirrels. They set up in 11 urban areas in Hokkaido, Japan, that were away from major roads and close to trees or bushes.

The locations were key, according to Pizza Ka Yee Chow, the leading author of the paper and a postdoctoral research fellow at Max Planck Institute for Ornithology in Germany. It minimized risk to the squirrels from predators or cars and it allowed them to feel comfortable and safe.

Researchers initially placed hazelnuts in the location to attract squirrels. Once they knew squirrels were visiting the site after about 3 to 5 days, they set up a box for a problem-solving task.

On the first day, the box stood alone without any levers with scattered hazelnuts all around. This was to help minimize fear of a new object, Chow explains.

“Once the squirrels were happily eating next to the box, we inserted the levers inside the box and there would be no more free nuts for squirrels,” Chow tells Treehugger. “If they want the nuts, they had to solve the problem.”

The successful solutions to the puzzle were counterintuitive. The squirrel had to push a lever if it was close to a nut and it had to pull a lever if it was far away from a nut.

What Affected Problem-Solving

Chow and her team tracked if the squirrels solved the problem and how quickly they managed to do it. They also recorded the urban characteristics in each site: direct human disturbance (mean number of humans present per day), indirect human disturbance (number of buildings within and surrounding an area), tree coverage of the area, and number of squirrels in the area.

They correlated these environmental factors with the squirrels’ problem-solving performance.

They found that 71 squirrels in the 11 areas tried to solve the problem and slightly more than half of them (53.5%) were successful. Researchers found that the success rate decreased in areas with more humans in a site, more buildings around a site, or more squirrels in a location.

However, for squirrels that were successful in solving the problem, they became faster over time in locations where there were more people and more squirrels.

“The enhanced learning performance could reflect squirrels quickly solving the problem in case a human approaches (and thus, perceives humans as potential threats),” Chow says. “The enhanced learning performance also reflects there is intra-specific competition (squirrel-squirrel competition) on the same food sources.” 

The study results have possible implications for human-wildlife conflict management, Chow says.

“For example, we may consider increasing the buffer zone between the activity area for humans and the activity area for wildlife in urban parks so that there would be an optimal space, both for humans and wildlife, while keeping some distance from each other.”

The results were published in the journal Proceedings of the Royal Society B.

View Article Sources
  1. Chow, Pizza Ka Yee, et al. "Characteristics of Urban Environments and Novel Problem-Solving Performance in Eurasian Red Squirrels." Proceedings of the Royal Society B: Biological Sciences, vol. 288, no. 1947, 2021, doi:10.1098/rspb.2020.2832