Seasonal changes in problem-solving in wild African striped mice.

Innovative problem-solving ability is a predictor of whether animals can successfully cope with environmental changes. These environmental changes can test the limits of animals, for example when energy availability decreases seasonally and, hence, problem-solving performance decreases because less energy is available for cognitive processes. Here, we investigated: (1) how problem-solving performance changed between seasons that differed significantly in food availability; (2) whether these changes were related to environmentally induced physiological changes in blood glucose and ketone levels, indicators of energy availability; and (3) whether individual variation in problem-solving was related to sex differences. We studied 99 free-ranging African striped mice, Rhabdomys pumilio, in the Succulent Karoo, South Africa, 55 during the hot dry summer with low food availability and 44 during the cold wet winter with higher food availability. We measured their problem-solving abilities using a food extraction task and found no seasonal differences in problem-solving success. However, mice solved the problem faster in summer versus winter. In summer, food availability was reduced and blood ketones increased but there was no seasonal difference in blood glucose levels. There were no correlation between problem-solving performance and blood glucose or ketone levels. Overall, more males solved the task than females. It appears that in striped mice cognitive functions can be maintained under harsh environmental conditions.