Family Calomyscidae
mouse-like hamsters

Calomyscidae is a small family of muroid rodents, with 8 species in 1 genus, Calomyscus. The members of this family are known as the mouselike hamsters. (Musser and Carleton, 2005; Steppan, Adkins, and Anderson, 2004)

Calomyscids range from western Pakistan throughout Afghanistan and Iran to southwest Syria, and north to southern Turkmenistan. (Nowak, 1999)

These rodents inhabit barren, rocky hills in the dry parts of their range, and hillsides covered with evergreen oaks in the parts of their range that receive monsoons. They live at elevations from 400 to 3500 meters. (Nowak, 1999; Tofts, 2003)

This unusual family of rodents seems to have characters in common with both Old World and New World muroid groups. Calomyscids have previously been placed within the new world subfamily Sigmodontinae (Pavlinov 1980), within the Old World subfamily Cricetinae in the family Muridae (Ellerman 1940, 1941), within the subfamily Cricetinae in the family Cricetidae (Chaline et al. 1977) and grouped as their own subfamily within the family Cricetidae (Vorontsov and Potapova 1979). It has also been suggested that they belong within a group of otherwise extinct muroids, the Cricetodontines (Carleton and Musser 1984). Recent molecular evidence suggests that Calomyscus is an isolated branch of the muroid rodent tree (Steppan et al. 2004; Jansa and Weksler 2004; Michaux et al. 2001). Its lack of similarity to any other muroid group has led to its recent placement in its own family (Steppan et al. 2004). (Carleton and Musser, 1984; Chaline, Mein, and Petter, 1977; Ellerman, 1940; Ellerman, 1941; Jansa and Weksler, 2004; Michaux, Reyes, and Catzeflis, 2001; Pavlinov, 1980; Steppan, Adkins, and Anderson, 2004; Vorontsov and Potapova, 1979)

Calomyscids are small and mouselike in overall appearance, hence the common name of the family. The length of the head and body ranges from 61 to 98 mm, the length of the tail ranges from 72 to 102 mm, and the weight ranges from 15 to 30 grams. There is no apparent sexual dimorphism. The tail is at least as long as the head and body combined, and the ears are large and prominent. The fur is fine and soft; the dorsal surface is pinkish, sandy or gray-brown and the paws and venter are white. The top of the tail is dark and the underside is white, it is covered in thick fur and has a tuft at the tip. There are six mammae. Unlike hamsters in the subfamily Cricetinae, calomyscids lack cheek pouches and sebaceous flank glands. (Nowak, 1999; Tofts, 2003; Vorontsov and Potapova, 1979)

No information is available on the longevity of mouselike hamsters, although it is likely that they live only about 1 to 2 years in the wild.

Calomyscids are active year round. In summer they are strictly nocturnal, but they are active at any time of the day or night in the fall and winter. They are good climbers, but never forage far from a rock crevice where they can seek shelter quickly. Calomyscids are not highly social; however, they sometimes nest in the same rock crevices or huddle together for warmth. In captivity, individuals can coexist peacefully in the same cage. Captive individuals are reported to be inquisitive and eager to investigate any disturbance that takes place near their enclosure. (Nowak, 1999; Tofts, 2003)

Like many other muroid rodents, calomyscids probably have keen senses of smell and touch. Their large, prominant ears indicate that they have a good sense of hearing as well. They are usually silent, but they do sometimes emit high-pitched chirps that may function in communication. (Tofts, 2003)

Seeds make up the main portion of the calomyscid diet, but flowers and leaves are eaten as well. In addition, these rodents readily eat animal matter, including insects and sometimes carrion. (Nowak, 1999; Tofts, 2003)

There are no reports of predation on calomyscids. However, they are most likely eaten by predators that consume other rodents, such as owls, snakes, and small carnivorous mammals. Calomyscids are extremely agile and adept at escaping would-be predators. When threatened, they dart into the nearest rock crevice for shelter. If caught in the open, they are capable of running very fast and jumping over 30 cm into the air to evade pursuers. (Nowak, 1999; Tofts, 2003)

Mouselike hamsters are primary and secondary consumers and they are, in turn, consumed by other animals.

There are no known negative impacts of calomyscids on humans.

Calomyscids have been imported into Europe by zoos in recent years and are sometimes kept as pets by rodent enthusiasts. They have also been used for research in Russian laboratories. (Tofts, 2003)

Hotson's mouse-like hamster (Calomyscus hotsoni) is listed as endangered by the IUCN. Three other species are listed as lower risk: Afghan mouse-like hamster (Calomyscus mystax), Tsolov's mouse-like hamster (Calomyscus tsolovi), and Urarstk mouse-like hamster (Calomyscus urartensis). Sightings of calomyscids in the wild are rare, and much research is still needed to fully understand the biology of this family of rodents and to assess the status of their populations. (IUCN, 2004; Tofts, 2003)