Squirrels are adaptable, opportunistic omnivores whose diet shifts seasonally, but seeds and nuts form an energy-dense foundation for their foraging efforts. These small mammals require a diet rich in fats and protein, especially when preparing for colder months or during high activity. Seeds are a concentrated source of calories, which is important for species that remain active throughout the winter. Ultimately, the successful management of their diet directly influences their survival and reproductive success in the wild.
Preferred Seeds in the Squirrel Diet
Squirrels prioritize seeds with high fat and oil content for maximum caloric return. Black oil sunflower seeds are a favorite due to their high oil content and thin, easy-to-crack shell. These seeds provide a quick burst of energy, which is essential for a creature that spends a significant portion of its day foraging.
Garden and wild seeds, such as those from pumpkin, squash, and melon, are also targeted for their healthy fats and protein. While species like the North American red squirrel specialize in seeds from coniferous cones, the more generalized gray squirrel consumes a wider variety of deciduous tree seeds. Common feeder seeds like sunflower and pumpkin have a high phosphorus-to-calcium ratio, meaning they should only be a small part of a wild squirrel’s diet. If consumed as a staple, these seeds can cause nutritional imbalances.
Seeds That Are Toxic or Harmful
Certain seeds and pits contain compounds that can be harmful, especially in human-supplied food. The seeds and pits of fruits like apples, cherries, peaches, and apricots contain cyanogenic glycosides, specifically amygdalin. When chewed, this compound releases toxic hydrogen cyanide. Although squirrels usually avoid ingesting whole pits, toxicity occurs if the inner kernel is consumed.
Processed seeds present dangers, as ingredients like salt and preservatives are unsuitable for a squirrel’s physiology. Heavily salted seeds can cause dehydration and kidney problems, which they are ill-equipped to manage. While corn is often in feeder mixes, an exclusive diet of it offers poor nutritional value and leads to deficiencies. Seeds treated with pesticides or chemical fertilizers must also be avoided, as these toxins build up in the animal’s system.
The Mechanics of Seed Consumption and Caching
Seed consumption begins with the squirrel’s specialized incisors, which gnaw through the hard outer husk to reach the soft kernel inside. This shelling process is a necessary mechanical action that accesses the food and helps keep their continuously growing teeth worn down. Once the shell is removed, the kernel is consumed, providing immediate energy for their active lifestyle.
Seeds also play a role in the squirrel’s long-term survival strategy through caching. Gray squirrels primarily engage in scatter hoarding, burying individual seeds and nuts in numerous shallow holes for later retrieval, relying on spatial memory and scent. This behavior is ecologically significant because the seeds they forget or fail to recover have the chance to germinate, effectively planting new trees. Conversely, species like the red squirrel often practice larder hoarding, storing a large quantity of seeds, such as conifer cones, in one central, defended location.