Rodent
A mammal in the order Rodentia, distinguished by a pair of continuously growing incisors in each jaw that are adapted for gnawing.
Rodentia: The mammalian order containing rodents, including mice, squirrels, beavers, and porcupines. Rodent is the common name for a member of this order.
Hypselodont tooth: A tooth that continues growing throughout an animal’s life. Rodent incisors are hypselodont, replacing material worn away during gnawing.
Laboratory mouse: A domesticated mouse bred and maintained for scientific research. Its tractable genetics and well-studied biology make it a widely used rodent model.
Lagomorpha: The mammalian order that includes rabbits, hares, and pikas. Lagomorphs resemble rodents but have a second pair of small upper incisors and belong to a separate order.
Incisor: A front tooth adapted for cutting or gnawing, found in mammals and several other vertebrates. Rodents are defined by their distinctive continuously growing incisors.
Tooth enamel: The hard, mineral-rich outer covering of a tooth crown. Uneven enamel on rodent incisors creates a self-sharpening cutting edge as the tooth wears.
Laboratory rat: A domesticated form of the brown rat used in biomedical and behavioral research. Rats support experiments on physiology, behavior, and disease that complement mouse studies.
Shrew: A small insect-eating mammal in the order Eulipotyphla, often mistaken for a mouse. Shrews share a small body shape with mice but have pointed teeth and are not rodents.
Diastema: A gap between teeth, especially the space separating incisors from cheek teeth in many mammals. This gap leaves room for rodents to gnaw while keeping their cheek teeth clear.
Malocclusion: A misalignment of teeth that prevents them from meeting normally. Without opposing teeth to wear them down, rodent incisors can overgrow dangerously.