Rabbits are a beloved pet for many people. One fact that a lot of people, even rabbit owners, do not realize, is that rabbits do not belong to the taxonomic order of rodents. Rabbits are part of the order of lagomorphs, known as the Lagomorpha order.
To understand what makes rabbits different than rodents, it is necessary to understand what properties make an animal fit into the rodent family. To do that, one must learn about the taxonomic order Rodentia.
What Defines a Rodent?
The order Rodentia is made up of many recognizable rodents including mice, rats, guinea pigs and squirrels. It also includes several animals that aren’t commonly thought of as rodents, such as capybaras, beavers and prairie dogs. This order is one of the largest groups of mammals, comprising approximately 1,500 living species out of 4,000 living mammals.
Animals are classified as rodents by examining their bodily characteristics, with heavy focus on the teeth. Rodents will only have a single pair of incisors in each jaw which grow throughout the rodent’s life. The incisors are coated with hard enamel which allows them to gnaw on hard surfaces that keep their teeth at a manageable length. They also tend to have a gap beside the incisors, so they are easier to use. Rodents don’t have canine teeth and only have a few molars at the back of their jaws.
Other defining features of rodents include their ability to adapt to environmental changes, quick and prolific breeding, a typically small stature to hide from predators (except for the capybara) and the ability to hibernate if they live in the cold or to estivate in hot environments.
What Defines a Rabbit?
Rabbits were classified as rodents until 1912 when James W. Gidley proposed moving them to the Lagomorpha order after several decades of paleontologists’ research. The Lagomorph order was relatively new, established in 1855. Through this research, Gidley and others realized that there were some striking differences between rodents and rabbits that would culminate into the eventual shift to the Lagomorph order.
For instance, while a large portion of rodent classification focuses on their teeth, a rabbit’s teeth do not fit into that classification. Rabbits have two sets of incisors instead of the standard single set and they have more teeth than rodents overall. The enamel of rabbits’ teeth is also different, covering both sides of the tooth rather than just the front. The incisors are a different color due to a lack of iron salts.
A lesser-known difference between rodents and rabbits that contributed to their reclassification is their diet. Rabbits are obligate herbivores which means they can only obtain their nutrients from plant matter and their digestive systems are not capable of handling animal matter. Conversely, rodents are capable of digesting animal matter and some species, called opportunistic omnivores, benefit from this. Rats are a good example of this, as they are able to live off carcasses if needed. For instance, Norway rats benefit from a high-protein diet of meat.
These are some of the biggest differences that separate rabbits from the order of Rodentia and what ultimately led them to being grouped into the better-fitting taxonomical classification of Lagomorphs.