When observing squirrels, many people notice their cheeks bulging, holding a surprising amount of food. This common sight prompts questions about how these small creatures manage such a feat and why they engage in this behavior. The ability to stuff their cheeks is a specialized adaptation found in certain squirrel species, serving as a strategy for efficiently gathering and transporting resources. This behavior supports their daily needs and long-term survival.
The Evolutionary Reason
Squirrels stuff their cheeks primarily for efficient food acquisition and storage, a behavior known as caching. This allows them to quickly collect large quantities of provisions. Many species, particularly ground squirrels, prepare for periods when food is scarce, such as during winter months. By gathering and transporting food in their cheek pouches, squirrels build up reserves for sustenance when foraging becomes challenging.
This adaptation enables them to capitalize on abundant food sources, ensuring a steady supply during lean times. Caching is a crucial survival mechanism, reducing the risk of starvation when resources are limited. Squirrels also selectively cache highly nutritious items like nuts and seeds, which have a longer shelf life, making them ideal for long-term storage. Some squirrels even excise the embryos from acorns before burying them to prevent germination, thereby prolonging their edibility.
The Mechanics of Cheek Pouches
Not all squirrels possess these cheek pouches; they are primarily found in ground squirrels, chipmunks, and prairie dogs, but not in tree squirrels or flying squirrels. These pouches are elastic, sac-like extensions of the oral cavity, located between the jaw and the cheek. They can stretch significantly, sometimes to nearly the size of the animal’s head when completely full.
Specialized muscles facilitate the function of these pouches, allowing squirrels to expand them to hold a surprising volume of items. Squirrels utilize their forepaws to efficiently pack food into the pouches and later to push the contents back out into their mouths. Food held within these pouches is for temporary storage and transport, not for immediate consumption or swallowing.
How This Behavior Ensures Survival
The ability to stuff their cheeks offers squirrels several practical advantages for their survival. It allows them to collect and carry more food in a single trip, which significantly increases foraging efficiency and reduces exposure to predators in open environments. This rapid collection and retreat minimize their vulnerability to threats while gathering food.
Once their pouches are filled, squirrels can transport the collected food to safer locations, such as their burrows or hidden caches, for later consumption or storage. This conserves energy by reducing the need for multiple trips and ensures that food is secured away from competitors or potential pilferers. The long-term benefit of caching, particularly scatter hoarding where food is buried in numerous small locations, provides a reliable food source during harsh conditions or low natural food availability.