Little is known about methods of communication. A similar species, Dipus sagitta, however, has been noted to make whinnying or moaning noises. Jerboas have excellent hearing and sight. Like other rodents, they also have a keen sense of smell and probably use olfactory cues extensively in communication (Ognev, 1963).
Communication Channels: acoustic ; chemical
Perception Channels: visual ; tactile ; chemical
Comb-toed jerboas are considered a species of lower risk/least concern by the IUCN Red List of Threatened Species.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
There are no known adverse effects of comb-toed jerboas on humans. Possible adverse effects of other jerboas that might apply to this species are spread of plague (Yersinia pestis) when caught as pets and the gnawing of roots from plants sometimes used as a source of food by people. However, these adverse effects are generally considered insignificant even for other species of jerboas (Ognev, 1963).
Paradipus ctenodactylus has no known economic value to humans, aside from their role as members of healthy, native desert ecosystems.
As it is very difficult to observe in the wild, little is known about the role of Paradipus ctenodactylus in the ecosystem. They may influence vegetation communities through their feeding habits and probably provide an important prey base for their predators. There are a number of flea species known to parasitize comb-toed jerboas.
Commensal/Parasitic Species:
Comb-toed jerboas are completely herbivorous, eating only desert shrubs. Although they eat a variety of plant parts and species, they are highly discriminatory with respect to plant species eaten and are selective as to which parts they eat (Ognev, 1963). Individual differences as well as seasonal and locality differences in food preferences have been noted (Prakash and Ghosh, 1975). Identified foods include shoots of Salsola richteri, Haloxylon persicum, and Calligonum arborescens, flowers and leaves of Calligonum caputmedusae, Calligonum arborscens, Ammodendrum conollyi, Astragalus paucijugus, Artemesia ereocarpa, and Acanthophyllum borszewi, the seeds or ovaries of Ammodendrum conollyi, Aristida karelini, Horaninovia ulicina, Malcolmia bungei, Corispermum papillosum, Euphorbia heirolepis, and the fruit of << Haloxylon persicum>> and Peganum harmala (Ognev, 1963; Prakash and Ghosh, 1975).
Their remarkable ability to climb shrubs using their forelimbs and teeth, use their hind legs to leap high into shrubs, and their balance allows this species to find and obtain food in desert shrubs and trees. Once the food is obtained, rather than being dragged back to the burrow, the food is dragged to an open area at the top of a sand dune to be eaten (Shenbrot et al., 1999).
Plant Foods: leaves; wood, bark, or stems; seeds, grains, and nuts; flowers
Primary Diet: herbivore (Folivore )
The comb-toed jerboa, Paradipus ctenodactylus, occurs from southwestern Turkmenistan bordering the Caspian Sea northeast to the Syr Darya River in Kazakhstan (Corbet, 1978). The species is found specifically in the Kyzyl Kum desert of Uzbekistan and Kazakhstan and southern Kara Kum desert of Turkmenistan (Prakash and Ghosh, 1975).
Biogeographic Regions: palearctic (Native )
Paradipus ctenodactylus is a psammophile found in the sandy Kyzyl Kum and Kara Kum deserts (Prakash and Ghosh, 1975). It is found concentrated in regions of these deserts with bushy vegetation such as sand acacia, calligonum, and tufts of three-awn. In these areas it is more common than any other rodent (Ognev, 1963).
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: desert or dune
Lifespan has not been recorded for P. ctenodactylus, but two other species of jerboa, Scirtopoda telum, the thick tailed three toed jerboa, and Allactaga sibirica, the jumper jerboa, have both been observed to live around 2 years in the wild. Only 3 to 7% lived to 3 years in both species (Prakash and Ghosh, 1975).
Comb-toed jerboas are similar to other jerboas. Like most jerboas, the eyes and ears are large, the tail is long, and the front limbs are short while the hind limbs are extremely elongated, lending themselves to the group's saltatorial mode of locomotion. The fur is a pinkish cinnamon to beige with white underparts and a broad white zone around each eye. There are rusty colored patches on the cheeks and chest and the tail has a large white tuft at the end (Nowak, 1991).
The length of the head and body is 110 to 155 mm and average weight is 140 g. The tail is not prehensile and is very long, approximately 206 to 221 mm (Nowak, 1991). Relative to other jerboas, the hind feet are very long at 73 to 82 mm (Ognev, 1963). These highly specialized hind limbs allow leaps of up to 3 m in length and 1 m in height and allow for surprising agility climbing shrubs as well. The three toes of the hind feet have a comb of stiff bristles with the longest bristles located on the medial toe and internal edges of the outer toes. These combed toes, from which the species' common name comes, are thought to assist in moving about the sandy habitat. Although the forelimbs are reduced, they are used for burrowing and have prominent claws, around 7 mm in length, which also assist in climbing and collecting food. The ears are longer than those of most other jerboas, at 33 to 38 mm (Nowak, 1991). Compared to other species in the subfamily Dipodinae, the cervical portion of the vertebral column is shorter, with complete fusion from vertebrae 2 to 6. Paradipus ctendactylus has white upper incisors, without the medial groove that is present in some jerboas. Premolars are absent (Ognev, 1963).
Average mass: 140 g.
Range length: 110 to 155 mm.
Sexual Dimorphism: sexes alike
Other Physical Features: endothermic ; bilateral symmetry
Little is known about the interactions of Paradipus ctenodactylus with other species, as it is hard to observe P. ctenodactylus in the wild. When threatened, however, comb-toed jerboas make short dashes to escape. They are the fastest of any jerboa species, reaching speeds up to 180 m per minute, but they tire quickly. When disturbed in their burrows, these animals respond by digging deeper into the sand, since they do not construct emergency exits (Ognev, 1963). Other jerboas are known to be prey to foxes, ermines, owls, cats, and steppe polecats (Ognev, 1963).
Anti-predator Adaptations: cryptic
Little is known about the reproductive habits of Paradipus ctenodactylus. A closely related species, Dipus sagitta, the rough legged jerboa, has been more closely studied. Dipus sagitta breeds in the same season as P. ctenodactylus and appears to have other similarities as well. During breeding season, D. sagitta males often fight over females. Males have been observed with multiple injuries and are occasionally even killed in these fights.
It has been suggested that the April-May period of breeding in both P. ctenodactylus and D. sagitta may include mostly older females, while the July period may also include yearling females (Prakash and Ghosh, 1975). Although D. sagitta has been observed breeding in its first year, at as early as 2 months of age, D. sagitta generally does not reproduce before one year of age. The gestation period is approximately 25 to 30 days. Litter size is around 2 to 5 young for D. sagitta. The young are born helpless and remain in the burrow for several months, until the middle of the summer to September (Ognev, 1963).
Breeding interval: Breeding intervals have not been well-studied in comb-toed jerboas.
Breeding season: Breeding seems to occur in April and May and again in July.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Little is known about parental investment in comb-toed jerboas but, like other mammals, females care for and nourish their young at least through the age of weaning.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female)
