The impact the urban environment has on squirrels’ problem-solving, learning and memory has been highlighted in new research from the University of Chester and Hokkaido University in Japan.

The study, focusing on the cognitive effects of urban living on Eurasian red squirrels, found greater effect than previously understood.

Exploring how the urban conditions affect squirrels, researchers set tests to evaluate the creatures' cognitive performance.

Using 11 urban areas in Obihiro, Japan, the research built upon a prior study that discovered certain characteristics of an urban environment could both hinder and enhance a squirrel's problem-solving prowess.

In this new study, the team pursued the theory of a 'ripple effect' on the squirrels' cognition, such as their capacity for generalisation - resolving a similar yet distinct problem - or their ability to recall information after extended time periods.

38 squirrels successful in solving an original problem were selected to further test their abilities.

The effects of urban characteristics like the presence of humans, the number of buildings, and the level of green coverage were evaluated.

The researchers found varying outcomes - either a decrease or increase in the squirrels' performance in memory tasks, depending on the combination of urban conditions.

Increased human disturbance, for instance, led to less success in problem-solving or memory tasks for the squirrel population.

Namio solving the generalisation box task.  (Image: University of Chester)

However, some features like frequent human disturbance coupled with less green space resulted in quicker problem-solving at individual levels.

Dr Pizza Ka Yee Chow, lead researcher and lecturer in the School of Psychology at the University of Chester said: "Such a threat is often unpredictable and may cause frequent interruptions when they are solving the task, causing some squirrels to give up and forage elsewhere or others to quickly solve the task and retreat to a tree for safety or to minimise their exposure to threats."

Dr Chow further commented: "Despite investigations into the effect of urban environments on aspects such as wildlife physiology and behaviour, the relationship between urban environments and wildlife cognition has remained largely unclear."

She added, "Our results partially support the ripple effect hypothesis, suggesting that urban environmental characteristics are stressors for squirrels and have a greater impact on shaping cognitive performance than previously shown."