The cricetids are small mammals, ranging from just 5–8 cm (2.0–3.1 in) in length and 7 g (0.25 oz) in weight in theNew World pygmy mouse up to 41–62 cm (16–24 in) and 1.1 kg (2.4 lb) in themuskrat. The length of their tails varies greatly in relation to their bodies, and they may be either furred or sparsely haired. The fur of most species is brownish in colour, often with a white underbelly, but many other patterns exist, especially in thecricetine andarvicoline subfamilies.
Like theOld World mice, cricetids are adapted to a wide range of habitats, from the highArctic to tropicalrainforests and hotdeserts. Some are arboreal, with long balancing tails and other adaptations for climbing, while others aresemiaquatic, with webbed feet and smallexternal ears. Yet others are burrowing animals, or ground-dwellers.[1]
Cricetids' populations can increase rapidly in times of plenty, due to a combination of shortgestation periods between 15 and 50 days, and large litter sizes relative to many other mammals. The young are typically born blind, hairless, and helpless.[1]
The cricetids first evolved in the Old World during the EarlyOligocene.[2][3] They soon adapted to a wide range of habitats, and spread throughout the world. The voles and lemmings arose later, during thePliocene, and rapidly diversified during thePleistocene.[4]
The circumscription of Cricetidae has gone through several permutations. Some members of the family as currently defined have been placed in the familyMuridae. Somemuroids have historically been placed in Cricetidae, such asmouse-like hamsters (subfamilyCalomyscinae, familyCalomyscidae), gerbils (subfamilyGerbillinae, family Muridae), thecrested rat (subfamilyLophiomyinae, family Muridae),zokors (subfamilyMyospalacinae, familySpalacidae), the white-tailed rat (subfamilyMystromyinae, familyNesomyidae), and spiny dormice (subfamilyPlatacanthomyinae, familyPlatacanthomyidae). MultigeneDNA sequence studies have shown the subfamilies listed below to form amonophyletic group (that is, they share a common ancestor more recently than with any other group), and other groups now considered muroids should not be included in the Cricetidae.[5]
The cricetids thus currently include one fossil and five extantsubfamilies, with about 112 livinggenera and 580species:
Eisenberg, J.F.; Feaver, J. & Krebs, C.J. (1984): Cricetidae. In:Macdonald, D. (ed.):The Encyclopedia of Mammals: 640–655, 672–673. Facts on File, New York.ISBN0-87196-871-1
Norris RW, Zhou KY, Zhou CQ, Yang G, Kilpatrick CW, Honeycutt RL (2004). "The phylogenetic position of the zokors (Myospalacinae) and comments on the families of muroids (Rodentia)".Mol. Phylogenet. Evol.31 (3):972–978.doi:10.1016/j.ympev.2003.10.020.PMID15120394.
Savage, R.J.G. & Long, M.R. (1986):Mammal Evolution: an illustrated guide. Facts on File, New York.ISBN0-8160-1194-X
Steppan SJ, Adkins RA, Anderson J (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.PMID15371245.
