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Temporal range: Early Miocene – Recent
|Black rat (Rattus rattus)|
The Muridae, or murids, are the largest family of mammals, containing over 700 species found naturally throughout Eurasia, Africa, and Australia. They have been introduced worldwide. The group includes true mice and rats, gerbils, and relatives.
The murids are small mammals, typically around 10 cm (3.9 in) long excluding the tail, but ranging from 4.5 to 8 cm (1.77 to 3.1 in) in the African pygmy mouse to 48 cm (19 in) in Cuming's slender-tailed cloud rat. They typically have slender bodies with scaled tails, and pointed snouts with prominent whiskers, but with wide variation in these broad traits. Many murids have elongated legs and feet to allow them to move with a hopping motion, while others have broad feet and prehensile tails to improve their climbing ability, and yet others have neither adaptation. They are most commonly some shade of brown in colour, although many have black, grey, or white markings.
Murids generally have excellent senses of hearing and smell. They live in a wide range of habitats from forest to grassland, and mountain ranges. A number of species, especially the gerbils, are adapted to desert conditions, and can survive for a long time with minimal water. They are either herbivores or omnivores, eating a wide range of foods in different species, with the aid of powerful jaw muscles and gnawing incisors that grow throughout life. The dental formula of murids is 220.127.116.11-3.
Murids breed frequently, often producing large litters several times per year. They typically give birth between 20 and 40 days after mating, although this varies greatly between species. The young are typically born blind, hairless, and helpless, although there are exceptions, such as the spiny mice.
As with many other small mammals, the evolution of the murids is not well known, as few fossils survive. They probably evolved from hamster-like animals in tropical Asia some time in the early Miocene, and to have only subsequently produced species capable of surviving in cooler climes. They have become especially common worldwide during the Holocene, as a result of hitching a ride with human migrations.
- Deomyinae (spiny mice, brush furred mice, link rat)
- Gerbillinae (gerbils, jirds and sand rats)
- Leimacomyinae (Togo mouse)
- Lophiomyinae (Maned rat or crested rat)
- Murinae (Old World rats and mice, including the vlei rats)
- Jansa, Sharon. A.; Weksler, Marcelo (2004), "Phylogeny of muroid rodents: relationships within and among major lineages as determined by IRBP gene sequences", Molecular Phylogenetics and Evolution 31 (1): 256–276, doi:10.1016/j.ympev.2003.07.002, PMID 15019624
- Michaux, Johan; Reyes, Aurelio; Catzeflis, François (1 November 2001), "Evolutionary history of the most speciose mammals: molecular phylogeny of muroid rodents", Molecular Biology and Evolution 18 (11): 2017–2031, ISSN 0737-4038, PMID 11606698
- Steppan, Scott; Adkins, Ronald; Anderson, Joel (2004), "Phylogeny and divergence-date estimates of rapid radiations in muroid rodents based on multiple nuclear genes", Systematic Biology 53 (4): 533–553, doi:10.1080/10635150490468701, PMID 15371245