
Rodents are mammals of the order Rodentia, which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents; they are found in vast numbers on all continents except Antarctica. They are the most diversified mammalian order and live in a variety of terrestrial habitats, including human-made environments.
Infanticide is the termination of a neonate after it has been born, and in zoology this is often the termination or consumption of newborn animals by either a parent or an unrelated adult. In rodents, it is not uncommon for the mother to commit infanticide shortly after parturition under conditions of extreme stress, or for an unrelated male to kill neonates.

Rodents are animals that gnaw with two continuously growing incisors. Forty percent of mammal species are rodents, and they inhabit every continent except Antarctica.

A mouse, plural mice, is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse. Mice are also a popular as pets. In some places, certain kinds of field mice are locally common. They are known to invade homes for food and shelter.

Oligoryzomys longicaudatus, also known as the long-tailed colilargo or long-tailed pygmy rice rat, is a species of rodent in the genus Oligoryzomys of the family Cricetidae. It is found in the southern Andes of Chile and Argentina, with an outlying population in eastern Argentina. As a common species with a wide range and a stable population, the International Union for Conservation of Nature has rated this rodent as being of "least concern".

Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus Rattus. Other rat genera include Neotoma, Bandicota and Dipodomys.

Voles are small rodents that are relatives of lemmings and hamsters, but with a stouter body; a shorter, hairy tail; a slightly rounder head; smaller ears and eyes; and differently formed molars. They are sometimes known as meadow mice or field mice in North America and Australia.