Greater Egyptian jerboa (Jaculus orientalis)
|Size||Body length: 7 - 15 cm (2)|
Tail length: up to 20 cm (2)
Average weight: 140 g (3)
Classified as Least Concern (LC) on the IUCN Red List (1).
The greater Egyptian jerboa has extremely long, kangaroo-like hind legs and feet, but comparatively tiny forelegs, which bear well developed claws and are used for sifting through sand to look for food (2). It has a pale sandy coloured coat and a long tail with a tuft of fur at the end (4), and large eyes and ears that enable it to detect fast movement and avoid predators. The greater Egyptian jerboa moves using just the two hind limbs (5), employing a hopping motion that enables the jerboa to move at fast speeds, while using minimal amounts of energy. This is owed to the spring-like mechanism of the legs, with the tendons and muscles storing elastic energy from previous jumps, greatly reducing the energy required for high speed movement (6). This mode of locomotion is thought to have evolved in response to jerboas occupying areas of low food availability and few natural shelters, making the conservation of energy and the ability to quickly escape predators vital (5).
The greater Egyptian jerboa occurs in North Africa (in Morocco, Algeria, Tunisia, Libya, and Egypt) and in Israel. It is most abundant and widespread in Algeria (1).
The greater Egyptian jerboa has a tolerance of a wide range of habitats, and has been found to occupy desert, coastal sand dunes, inland bogs and marshes, meadows, and cultivated land. It occupies altitudes from sea level to 600 metres in Israel, and far greater elevations in Africa (1). This species is able to survive in areas characterised by scarce water supplies and extreme temperatures, ranging from 45 degrees Celsius in summer to below freezing in winter (3).
A sociable animal, often found in small groups, the greater Egyptian jerboa is herbivorous, foraging for food throughout the night. Its diet consists of roots, shoots, leaves, and seeds of a variety of both wild and cultivated plants (1). It avoids the exhausting heat of the summer by spending the daytime in cool underground burrows (3), and survives the cold and resource-scarce winter months by hibernating (7).
Jerboas construct at least four different types of burrow of varying depths. These range from ten centimetre deep burrows, used to shelter from predators during the night, to burrows that measure over 220 centimetres deep for hibernation during winter (2).
Mating occurs shortly after emergence from hibernation (2). Compared to other rodents, jerboas have a long gestation period (six weeks) and weaning period, and do not become bipedal until around seven weeks after birth. Until this stage, the young jerboa moves slowly, using only the short forelegs to drag the trunk and hind-legs forward (8).
There are no major threats to this species, which is fairly widespread and common. However, it is killed by farmers in some areas, as it is considered a pest of certain crops (1), and this species suffers from a fairly high rate of infection from the parasite Isospora orientali, with nearly 70 percent of individuals infected in Egypt. Infection results in decreased food and water intake, and an increase in mortality (9).
There are currently no direct actions in place to protect the species, due to its non-threatened status, but it has been found in a number of protected areas (1).
Checked (24/08/10) by Dr Francis Gilbert, Associate Professor, University of Nottingham.
- Bipedal: the ability to walk on two hind limbs, rather than all four limbs.
- Gestation: the state of being pregnant; the period from conception to birth.
- Herbivorous: having a diet that comprises only vegetable matter.
- Hibernation: a winter survival strategy characteristic of some mammals in which an animal’s metabolic rate slows down and a state of deep sleep is attained. Whilst hibernating, animals survive on stored reserves of fat that they have accumulated in summer.
IUCN Red List (April, 2010)
- Anderson, S. and Jones, J.K. (1967) Recent Mammals of the World. The Ronald Press Company, New York.
- Hooper, E.T. and El Hilali, M. (1972) Temperature regulation and habits in two species of Jerboa, genus Jaculus. Journal of Mammology, 53: 574-593.
- Morris, D. (1965) The Mammals. Hodder and Stoughton, London.
- Rogovin, K.A. (1999) On the origin of bipedal locomotion in rodents (ecological correlates of jerboa's bipedal hopping). Zoologichesky Zhurnal, 78: 228-239.
- Taylor, C.R. (1985) Force development during sustained locomotion: A determinant of gait, speed and metabolic power. Journal of Experimental Biology, 115: 253-262.
- El Hilali, M. and Veillat J.P. (1975) Jaculus orientalis: a true hibernator. Mammalia, 39: 401-404.
- Eilam, D. and Shefer, G. (1997) The developmental order of bipedal locomotion in the jerboa (Jaculus orientalis) pivoting, creeping, quadrupedalism, and bipedalism. Developmental Psychobiology, 31: 137-142.
- Fayed, H.M. (2004) Developmental stages of pathogenicity of Isospora orientali sp. nov. (Apicomplexa, Eimeriidae) infecting the greater Egyptian jerboa Jaculus orientalis (Erxleben, 1777) (Rodentia, Myomorpha, Dipodidae): a light microscopic study. Journal of the Egyptian German Society of Zoology, 43: 61-85.