Jaculus orientalis

Geographic Range

Jaculus orientalis (greater Egyptian jerboa) can be found across North Africa in Morocco, Algeria, Tunisia, Libya, and Egypt. The species is especially common in Egypt and extends east through Sinai and into southern parts of Israel; formerly, the species inhabitated areas of Saudi Arabia.

• Biogeographic Regions
• palearctic palearctic
  • native native

Habitat

Jaculus orientalis lives in humid coastal and salt semi-deserts and in subtropical shrubland, including rocky valleys and meadows. They are also found in barley fields of the semi-nomadic Bedouin tribes.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• desert or dune desert or dune
• savanna or grassland savanna or grassland
• scrub forest scrub forest

• Other Habitat Features
• agricultural agricultural

Physical Description

Jaculus orientalis is covered in white fur ventrally and pale, yellowish-dark, sandy fur dorsally. Inner and outer ear areas are covered with thin hair. Eyelashes and sensory hairs are black, while the whiskers are a grey-white. The long tail is also covered with thin, short hair and ends in a tuft of black and white hair; the tail length averages 12.8 to 25 cm (5-9.8 inches). When standing, J. orientalis rests its tail in a curved position, providing support and balance. Males are slightly larger than females; average body mass is 139.1 g.

The body is very compact with a large head and limbs adapted for saltatorial locomotion. The hindlimbs are roughly four times as long as the forelimbs and are used for leverage when the animal jumps great distances. The metatarsal bones of the hind feet are fused together into a 'cannon bone,' and the first and fifth digits are missing, leaving three long, flattened toes. Hair on the sides and bottom of toes increase the surface area of the foot and aid in locomotion on sand.

Average basal metabolic rate is 3.649 kcal/kg/h and body temperature is 37.0 degrees Celcius.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger

Reproduction

There is limited information regarding the reproduction of J. orientalis primarily because of its nocturnal and burrowing behavior. Other members of the genus Jaculus display a particular courting behavior that involves the male standing upright in front of a female. He then lowers himself to the height of the prospective mate and slaps her regularly with his front limbs. It is believed that most desert jerboa species have a polygynous mating system.

• Mating System
• polygynous polygynous

Although captive breeding has been unsuccessful, it is known that J. orientalis breeds once a year. The breeding season is typically 5-6 months, starting in February and culminating in July. Females average 3 offspring per litter, but may have anywhere from 2-8 young each season. The gestation period is roughly 40 days long.

When a young J. orientalis is born, its forelimbs and hindlimbs are the same length, the tail is short, fur is absent, and the eyes and ears are closed. For the first 4 weeks, pups move by crawling with their forelimbs, dragging their body and hindlimbs along. After 4 weeks, quadruped locomotion emerges, and after about 47 days old they are capable of bipedal locomotion. In other members of Jaculus , particularly J. jaculus , offspring are born naked with short vibrissae, and relatively short hindlimbs and tail. They crawl with their forelimbs in the same fashion as J. orientalis . Jaculus jaculus young open their eyes after 5 weeks and eat solid food at 6 weeks. They are independent at 8-10 weeks and sexually mature at 8 to 12 months.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
• viviparous viviparous

After birth, the mother stays with the young in her burrow during the breeding and suckling season until the altricial offspring are self-sufficient. She provides the young with food and resources as well as the protection and shelter of the burrow. In addition, it is assumed that the mother teaches locomotion and survival skills until independence is reached, about the time of weaning. It is unknown if the male has a role in parental investment.

• Parental Investment
• altricial altricial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female

Lifespan/Longevity

The lifespan of J. orientalis in the wild is unknown; however, the offspring of a pregnant female captured for a study lived for over six years in captivity.

Behavior

Jaculus orientalis is nocturnal. These jerboas emerge from their burrows during late dusk and retreat at dawn. Related jerboas begin their nocturnal activities with a sand bath, removing oils and fat from their fur. They groom themselves with their paws and teeth each night. When in the burrow, they sleep most of the time or rest in a crouching position. If in a group, jerboas like to sleep on top of one another, helping to retain body heat in the winter months. They are social and play with each other; Bedouins have reported that the jerboas congregate in large burrows for "play" on some nights.

Greater Egyptian jerboas dig burrows into desert sand and clay by brushing away, pushing, or beating the soil. Burrows can range from 0.75 m to 1.75 m in depth and 1 to 2.5 m long. All burrows have a main chamber where the jerboa lives and most have an emergency exit tunnel as well. The nest is frequently lined with camel hair, dry shredded vegetation, and plant wool to keep the inhabitant warm. In rainy winters burrows are made on the sides of hills to avoid flooding, and the entrance is usually left open. In the summertime, burrows are usually on less elevated areas near vegetation; the entry hole is plugged with soil, possibly to prevent snakes and warm air from entering.

Earlier studies observed neither hypothermia nor temperature-induced torpor in Jaculus , suggesting that J. orientalis neither hibernated nor aestivated and was active year-round. However, Jaculus does not store food or have cheek pouches, and reports by Bedouins suggest that these animals disappear in the winter, implying extended below ground occupancy of burrows. This might be in response to extremely cold temperatures or food shortages. Later investigations supported this hypothesis and have depicted J. orientalis as an ideal model for deep hibernation. It has been found that during cold periods J. orientalis accumulates lipid reserves, developing a seasonal obesity. Following this accumulation, the jerboa's body temperature decreases to around 9.8°C and the heart frequency drops to about 9.3 beats/min; an active jerboa maintains a 37°C body temperature with a heart rhythm around 300 beats/min.

• Key Behaviors
• saltatorial saltatorial
• nocturnal nocturnal
• motile motile
• sedentary sedentary
• hibernation hibernation
• social social

Home Range

Since J. orientalis is nocturnal, it is difficult to assess their home range; however, during a field survey, 1 to over 50 individuals were counted over a distance of 0.8 km.

Communication and Perception

Jaculus orientalis is a social species, so different forms of communication are likely. However, only observations based on captive animals are available. Captive jerboas make sounds to display their anger or annoyance with other jerboas. They have also been observed rhythmically tapping and scratching the floor of their cages. The action gives the impression of communication; however, the animal might only be imitating digging movements used to create burrows in the wild. Communication with scent marking or pheromones is highly likely.

The related desert jerboa, J. jaculus , seems to recognize one another by smell when in captivity. Individuals close their eyes, come together until their noses touch, and remain in contact this way for 1 to 5 seconds.

Jerboas have keen hearing and eyesight, being well-adapted to their nocturnal habits. They also perceive chemical cues and vibrations.

• Communication Channels
• tactile tactile
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• pheromones pheromones
• vibrations vibrations

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• vibrations vibrations
• chemical chemical

Food Habits

Jaculus orientalis feeds primarily on succulent roots, sprouts, seeds, grains, a few cultivated vegetables, and occasional insects. They use their front paws to sift through sand and loose soil looking for seeds, to handle food, and to climb plants. Jaculus orientalis derives water from green vegetation and can live without drinking free-standing water for long periods of time. When related desert jerboa species do drink from a body of water, they dip their front paws in the water and then lick them, instead of drinking directly from the source.

• Primary Diet
• herbivore herbivore
  • granivore granivore

• Animal Foods
• insects

• Plant Foods
• leaves
• roots and tubers
• seeds, grains, and nuts

Predation

Jaculus orientalis is highly nocturnal and stays in the safety of its burrow during the day. However, if the animal feels threatened while inside, it can escape through an emergency exit tunnel. When alarmed at night, J. orientalis takes off towards its burrow or another safe, sheltered area. Its normal bipedal walking/running gait turns into great leaps as it flees a predator. These leaps have been measured at 1.5 to 3 m long and 1 m high. This is the animal's only mechanism of defense, and generally it cannot get away from a predator once captured. Common predators of J. orientalis include snakes, Rüppel's foxes, fennecs, owls, and humans.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

The herbaceous food habits and subsequent foraging behavior of J. orientalis influences its ecological community. When the animal sifts through the soil searching for seeds and other plant matter, it disperses seeds, particularly those too hard to eat, and aerates the soil. This can promote new plant growth and enhance water movement in the soil. Likewise, J. orientalis serves as a food source for carnivorous and omnivorous species in the ecosystem.

The burrow of J. orientalis may be used as a home by conspecifics when the homeowner dies, or by other rodent species. It is possible that even insects such as scorpions and spiders will make use of abandoned burrows. In addition, tiny ticks, mites, and lice live in the fur of jerboas.

• Ecosystem Impact
• disperses seeds
• soil aeration soil aeration

Economic Importance for Humans: Positive

Jaculus orientalis is hunted by Bedouin peoples for its meat, and sometimes its fur, used as trim. The Bedouin have three strategies for capturing jerboas. They pour water into burrows, forcing the animals to run out, they dig up burrows, or they set traps by burrow openings. In addition, J. orientalis is occasionally found on the pet trade due to its tame disposition and manageable size.

• Positive Impacts
• pet trade pet trade
• food food
• body parts are source of valuable material

Economic Importance for Humans: Negative

Jaculus orientalis has been known to eat barley and ripe from Bedioun agricultural fields, damaging the crop harvest. This negative impact often leads the Bedouin to intensify their hunting of the species.

• Negative Impacts
• crop pest

Conservation Status

In 1996, J. orientalis was designated as 'Lower Risk/Near Threatened' on the IUCN Red List of Threatened Species. In 2004, the species was re-assessed and its status improved to 'Least Concern,' where it now currently resides. This means the species is widespread and abundant.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Whitney Wiest (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.

References

Aulagnier, S. 2004. "Species Information- Jaculus orientalis " (On-line). 2004 IUCN Red List of Threatened Species. Accessed March 19, 2006 at http://www.redlist.org/search/details.php?species=10913 .

Eilam, D., G. Shefer. 1997. The developmental order of bipedal locomotion in the jerboa ( Jaculus orientalis ): Pivoting, creeping, quadrupedalism, and bipedalism. Developmental Psychobiology , 31/2: 137-142.

El Hilali, M., J. Veillat. 1975. Jaculus orientalis : A True Hibernator. Mammalia , 39: 401-404.

Ferguson, W. 2002. Mammals of Israel . Jerusalem: Gefen Publishing House.

Happold, D. 1967. Biology of jerboa, Jaculus jaculus butleri (Rodentia, Dipodidae), in the Sudan. Journal of Zoology, London , 151: 257-274.

Hooper, E., M. El Hilali. 1972. Temperature Regulation and Habits in Two Species of Jerboa, Genus Jaculus. Journal of Mammalogy , 53: 574-593.

Kirmiz, J. 1962. Adaptation to Desert Environment: A study on the jerboa, rat, and man . London: Butterworth & Co..

Nowak, R. 1991. Walker's Mammals of the World, 5th ed. . Baltimore and London: The Johns Hopkins University Press.

Vaughan, T., J. Ryan, N. Czaplewski. 2000. Mammalogy, Fourth Edition . London: Thomson Learning, Inc..

2002. "BBC- Science & Nature- Wildfacts" (On-line). Lesser Egyptian jerboa, desert jerboa- Jaculus jaculus . Accessed March 21, 2006 at http://www.bbc.co.uk/nature/wildfacts/factfiles/620.shtml .

2003. Family: Birch mice, jumping mice, and jerboas. Pp. 211-224 in Grzimek's Animal Life Encyclopedia , Vol. 16, 2 Edition. Detroit: Gale Group Inc..