When observing squirrels, a common question arises regarding their biological classification. Many wonder if these familiar creatures, with their bushy tails and busy habits, are scientifically considered rodents. Understanding their place within the broader animal kingdom requires exploring the specific characteristics that define different groups of mammals.
The Simple Answer
Squirrels are indeed classified as rodents. They belong to the order Rodentia, a scientific classification that includes a wide array of mammals. This grouping is based on distinct biological traits shared among all members of this order, rather than just general appearance or habitat. Their inclusion stems from specific anatomical features and behaviors.
Defining Rodents
The order Rodentia represents the largest group of mammals, encompassing over 2,000 species, which accounts for approximately 40% of all mammalian species. The term “rodent” originates from the Latin word “rodere,” meaning “to gnaw,” a direct reference to their most distinguishing characteristic. All members of this order possess a unique dental structure crucial for their survival.
Rodents are characterized by a single pair of continuously growing incisors in both their upper and lower jaws. These front teeth have a hard enamel layer on the front and softer dentine on the back. This allows the teeth to self-sharpen as they are used, creating a chisel-like edge. The constant growth of these incisors necessitates continuous gnawing to wear them down, preventing them from becoming excessively long.
Another defining feature is a gap, known as a diastema, between their incisors and their cheek teeth. Unlike many other mammals, rodents lack canine teeth. Their jaw muscles are also specifically adapted to facilitate the powerful gnawing motions required to manage their ever-growing teeth and process their varied diets.
Squirrels: Fitting the Rodent Profile
Squirrels belong to the family Sciuridae within the order Rodentia. Like all other rodents, squirrels possess the characteristic single pair of continuously growing incisors in both their upper and lower jaws. This biological trait is fundamental to their classification and daily activities.
The necessity for squirrels to gnaw constantly is a direct consequence of these ever-growing teeth. If they did not consistently wear down their incisors, the teeth would grow too long, potentially causing health complications and preventing them from eating effectively. This gnawing behavior is a biological imperative for their dental health and overall survival.
Squirrels gnaw on a wide range of materials, including tree bark, nuts, seeds, and bones, all serving to keep their incisors at a manageable length. The Sciuridae family is diverse, encompassing tree squirrels, ground squirrels, flying squirrels, chipmunks, and marmots. Despite differences in habitat and appearance, all these members share the core rodent characteristics.