Difference Between Rodents and Lagomorphs

The key difference between rodents and lagomorphs is that front of rodents incisors are surrounded by a double-layered, orange colour pigmented layer of enamel while the front of lagomorphs incisors are surrounded by a single, unpigmented layer of enamel.

Rodents and lagomorphs are two groups of mammals. The most noticeable feature of these two types of mammals is the continuously growing large chisel-shaped incisors and the distinct diastema between the incisors and the cheek teeth. Due to the presence of these incisors, rodents and lagomorphs have gained the ability of gnawing. Hence, both these group is collective called ‘gnawing mammals’. Rodents and lagomorphs cannot produce the cellulase enzyme, which helps to digest cellulose in plant materials they eat. Instead, they have certain bacterial species in their stomach to do this task. Despite these similarities, there is a distinct difference between rodents and lagomorphs.

CONTENTS

1. Overview and Key Difference
2. What are Rodents 
3. What are Lagomorphs
4. Similarities Between Rodents and Lagomorphs
5. Side by Side Comparison – Rodents vs Lagomorphs in Tabular Form
6. Summary

What are Rodents?

Rodents are the mammals belonging to the largest and most diversified order of living mammals: Rodentia. Rodents have an ever-growing pair of incisors in each jaw (upper and lower). Their bodies are robust with short limbs and long tails, but there are exceptions. Moreover, order Rodentia contains more than 30 families with some 1600 species.

Rodents are widespread and found in almost all the continents except Antarctica.  They live in a variety of terrestrial habitats including man-made environments. The order includes mice, rats, prairie dogs, squirrels, porcupines, guinea pigs, hamsters.

What are Lagomorphs?

Lagomorph is a Greek word that has the meaning of “hare-shaped”.  Rabbits, hares and pikas are the mammals that belong to this category or the order Lagomorpha. There are two families under this order. They are family Ochotonidae, which includes pikas, and family Leporidae, which includes hares and rabbits. Lagomorphs are found as native or introduced animals in all habitats including forests, grasslands, wetlands, deserts, and mountains in all the continents except Antarctica.

Rabbits and hares are widely spread and share more common features, including large eyes, long-eares and elongated limbs. Pikas have quite different morphological features from rabbits and hares such as small eyes, round ears and short limbs. All these species are specifically prey to many kinds of mammals and bird species but have broad adaptations to avoid their predators.

What are the Similarities Between Rodents and Lagomorphs?

• Rodents and lagomorphs are mammals.
• Both groups eat plant matter.
• However, they cannot produce cellulase enzyme, and they have bacteria in their gut for aiding the digestion process.
• They have continuously-growing large chisel-shaped incisors and the distinct diastema between the incisors and the cheek teeth.
• They also have hard enamel on the external surface of the incisors and a soft dentin behind
• Moreover, they don’t possess canine teeth.

What is the Difference Between Rodents and Lagomorphs?

Rodents have a double-layered, pigmented layer of enamel which cover only the front part of incisors while the incisors of lagomorphs are surrounded by a single, unpigmented layer of enamel. This is the key difference between rodents and lagomorphs. Mice, rats, prairie dogs, squirrels, porcupines, guinea pigs and hamsters are rodents while hares, rabbits and pikas are lagomorphs. Moreover, rodents have one pair of incisors while lagomorphs have two pairs of upper incisors.

Another difference between rodents and lagomorphs is that all the lagomorphs high-crowned cheek teeth, whereas only some members of rodents share this feature. In addition, maxillary fenestrations are present in lagomorphs, whereas they are absent in rodents. This is also a difference between rodents and lagomorphs.

The below infographic summarizes the difference between rodents and lagomorphs.

Summary – Rodents vs Lagomorphs

Rodents are the largest group of mammals that have upper and lower pairs of ever-growing rootless incisor teeth. Some common rodents are rats, mice, porcupines, beavers, squirrels, marmots, pocket gophers, and chinchillas. In contrast, lagomorphs are another group of mammals that have two pairs of ever-growing rootless incisor teeth. The key difference between rodents and lagomorphs is that rodents have a double-layered, pigmented layer of enamel which cover only the front part of incisors while the incisors of lagomorphs are surrounded by a single, unpigmented layer of enamel.

Reference:

1. “Rodent.” Wikipedia, Wikimedia Foundation, 16 Nov. 2019, Available here.
2. Smith, Andrew T. “Lagomorph.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 21 Mar. 2008, Available here.

Image Courtesy:

1. “Rodent collage” By Bobisbob – File:Capi.jpg: Jonas MaravalhasFile:Springharelg.jpg: DevonpikeFile:Goldmantelziesel.jpg: EboruttaFile:American Beaver.jpg: SteveFile:House mouse.jpg: National Institutes of Health (NIH) (CC BY-SA 3.0) via Commons Wikimedia
2. “Oryctolagus cuniculus Tasmania 2” By JJ Harrison – Own work (CC BY-SA 3.0) via Commons Wikimedia