Despite superficial similarities, rabbits are not rodents. Historically, rabbits were grouped with rodents due to shared traits like continuously growing teeth. However, scientific classification has clarified that rabbits belong to a distinct mammalian order. This reclassification reflects fundamental biological and anatomical differences that set them apart from true rodents.
Key Differences from Rodents
A key distinction is their dental structure. Rabbits possess two sets of upper incisors: a prominent front pair and a smaller, peg-like pair located directly behind them. Rodents, in contrast, have only a single pair of upper incisors. While both have continuously growing incisors, all of a rabbit’s teeth (incisors and cheek teeth) grow continuously, unlike most rodents where only incisors do. Additionally, rabbit incisors are typically white, differing from the often orange-colored incisors found in many rodents.
Dietary adaptations also differ. Rabbits are obligate herbivores, meaning their diet consists almost exclusively of plant material. Rodents, however, exhibit a much broader range of diets, with many species being omnivores. A unique digestive process called cecotrophy helps rabbits extract maximum nutrients from their fibrous plant-based diet. They produce specialized soft fecal pellets, called cecotropes, which are re-ingested to absorb essential vitamins and proteins fermented in their large cecum. While some rodent species also practice cecotrophy, it is less central to their digestive strategy.
Skeletal and muscular structures also show distinct differences. Rabbits possess powerful hind limbs adapted for a hopping form of locomotion. This contrasts with the scurrying gait typical of many rodents. Their bones are relatively light, contributing to their agility. Furthermore, unlike rodents, rabbits lack paw pads; the soles of their feet are entirely covered with fur.
Reproductive biology also differs. Female lagomorphs are often larger than males, a characteristic not universally found in rodents. Rabbits have high reproductive rates, being induced ovulators and producing multiple large litters throughout the year. Male rabbits also lack a baculum, a bone found in the penis of many rodent species.
The Lagomorph Order
Rabbits belong to the scientific order Lagomorpha. The name “Lagomorpha” itself derives from Greek words meaning “hare-shaped,” reflecting the general appearance of its members. This order was formally established in 1855, distinguishing these animals from rodents, where they were previously misclassified.
All lagomorphs share several defining characteristics. They possess the unique dental arrangement of two pairs of upper incisors, including the smaller peg teeth. Their teeth continuously grow throughout their lives, necessitating constant chewing to prevent overgrowth. Lagomorphs are also exclusively herbivorous.
Beyond rabbits, the Lagomorpha order includes hares, which are larger with longer ears and legs, and pikas, smaller mammals with rounded ears and virtually no tail. These species demonstrate the order’s diverse adaptations while maintaining core biological features that differentiate them from rodents.