Rodents

Rodents, or the order Rodentia, are a diverse group of mammals distinguished by a single pair of continuously growing incisors in each of the upper and lower jaws. These teeth are kept sharp by gnawing and are typically chisel-shaped with enamel on the front surface. Most rodents lack canines and have a diastema between the incisors and the molars. The group comprises thousands of species, including mice, rats, squirrels, beavers, hamsters, guinea pigs, and many others. Rodents inhabit nearly every terrestrial habitat, from deserts and forests to mountains and urban areas, and some, such as beavers, are semi-aquatic.

Incisors grow throughout life and are paired with flat grinding molars. Diets vary from strictly herbivorous to omnivorous, depending on species. Some specialize on seeds, tubers, or bark, while others forage opportunistically in human environments.

Rodents are often prolific breeders and display a wide range of social structures, from solitary to highly social. They play important ecological roles as seed dispersers, prey, and ecosystem engineers; beavers, for example, shape waterways through dam building, while many burrowing species aerate soils.

Several species, notably the house mouse and brown rat, live commensally with people and can damage crops, stored food, and infrastructure, and can spread disease. Others are valued as research animals or as food sources. Conservation status ranges from abundant to endangered, with habitat loss and invasive species threatening certain island and specialist rodent taxa.