WTF Fun Fact 13672 – Squirrels’ Brains Get Bigger

Squirrels’ brains get bigger so they can remember where they buried their nuts. At least, that’s the theory!

The Science Behind Squirrels’ Brains Getting Bigger

Squirrels that engage in scatter-hoarding exhibit a level of methodical planning that rivals that of humans in complexity. They don’t just bury their food anywhere; they make calculated decisions on where and how to store each nut. This behavior involves assessing each nut’s weight, freshness, and potential infestation through methods like paw manipulation. Such detailed analysis requires a significant amount of cognitive processing.

Interestingly, the type of nut and its size influence how and where it’s stored. Larger nuts are buried less densely to prevent other animals from finding a jackpot. Meanwhile, smaller nuts like peanuts are scattered more broadly.

This not only showcases squirrels’ strategic planning but also their ability to categorize and organize their food sources spatially.

Squirrel Brain Change with the Seasons

The act of burying nuts isn’t just about survival through winter. This behavior is a cognitive exercise that may lead to physical changes in the brain.

Lucia Jacobs, a professor at the University of California-Berkeley, posits that the intense period of nut storage is linked to observable growth in squirrel brains. This growth isn’t permanent, however. Brain sizes fluctuate with the seasons, enlarging during the autumnal nut-gathering frenzy and reducing thereafter.

This seasonal brain change isn’t unique to squirrels!

Shrews experience a reduction in brain size to conserve energy during winter, a phenomenon known as the Dehnel effect. Unlike shrews, squirrels live much longer and thus exhibit a cyclical pattern of brain enlargement and reduction correlating with their nut-gathering activities.

Squirrels Brains Get Bigger for Memory and Survival

The cognitive demands of scatter hoarding may enhance squirrels’ spatial memory. The constant interaction with their cache, through checking and sometimes relocating nuts, helps squirrels build a mental map of their stored food. This becomes crucial in winter, when finding food quickly can mean the difference between life and death. The ability to remember the location of their food stores allows squirrels to efficiently forage in the snow, minimizing exposure to predators.

The Bigger Picture

This research into squirrel behavior and brain size opens up new avenues for understanding animal cognition and seasonal adaptations. It challenges us to reconsider the intellectual capabilities of animals and their responses to environmental pressures. The insights gained from studying squirrels could inform broader studies on memory, survival strategies, and brain plasticity across species.

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Source: “In the autumn, squirrels think about nuts so much that it may make their brains bigger” — University of Michigan