Gerbillinaegerbils, jirds, and relatives

Di­ver­sity

Ger­bil­li­nae, oth­er­wise known as the ger­bils, jirds, and rel­a­tives, is a large Old World murid sub­fam­ily. This sub­fam­ily is one of the most well-de­fined in Muroidea. Its mem­bers have much in com­mon; most being di­ur­nal, salta­to­r­ial desert ro­dents. There are 103 ger­billine species in 16 gen­era. (Musser and Car­leton, 2005)

Ge­o­graphic Range

Ger­billines are Old World ro­dents. They are dis­trib­uted through­out Africa and the Mid­dle East, through cen­tral Asia in­clud­ing much of India, to east­ern Mon­go­lia. (Car­leton and Musser, 1984)

Habi­tat

Most ger­billines live in dry, open habi­tats with sparse veg­e­ta­tion, in­clud­ing deserts, sandy plains, moun­tain slopes, steppes, grass­lands, and sa­van­nahs. Some species also in­habit moist wood­lands, agri­cul­tural fields, and moun­tain val­leys. (Car­leton and Musser, 1984; Nowak, 1999)

Phys­i­cal De­scrip­tion

Ger­billines are small to medium-sized ro­dents. They range in length from 50 to 200 mm, with tails mea­sur­ing 56 to 245 mm. They weigh be­tween 10 and 227 grams. Ger­billines vary in the amount to which they are sex­u­ally di­mor­phic; even within a species males may be heav­ier than fe­males in one pop­u­la­tion and the sexes may be the same size in an­other pop­u­la­tion (Sinai et al. 2003). Most ger­billines have well-furred, long tails and are mod­i­fied for salta­to­r­ial lo­co­mo­tion, with long, nar­row hind feet. Some species are cur­so­r­ial. Ger­billines are gen­er­ally slen­der an­i­mals with long claws. They may have long or short ears. Their pelage is long, thick, and soft or short and harsh. Some have tufted tips on their tails. Fur color varies widely, and may be red­dish, mouse gray, yel­low­ish, clay-col­ored, olive, dark brown, orangish, sandy buff, or pink­ish cin­na­mon on the dor­sal sur­face. The un­der­parts are gen­er­ally paler shades of gray, cream, or white. Some species have whitish spots on their heads, es­pe­cially be­hind the ears.

The ger­billine den­tal for­mula is 1/1, 0/0, 0/0, 3/3 = 16, ex­cept for the genus Desmod­il­lis­cus, which only has two lower mo­lars on each side. The lay­ers of enamel on the in­cisors are very thin com­pared to other muroid ro­dents. The mo­lars are rooted, with lophate, pla­nar, or pris­matic enamel pat­terns. The coro­noid process is very small or ab­sent. Ger­billines have 12 tho­racic ver­te­brae and seven lum­bar ver­te­brae. Fe­males have three or four pairs of mam­mae. The stom­ach con­sists of just a sin­gle cham­ber. There are no supra­or­bital or mandibu­lar branches of the stape­dial artery, and in­stead, the in­fra­or­bital artery sup­plies blood to the or­bits. Ger­billines have diploid chro­mo­some num­bers be­tween 18 and 74. (Car­leton and Musser, 1984; Nowak, 1999; Sinai, et al., 2003)

  • Sexual Dimorphism
  • sexes alike
  • male larger

Re­pro­duc­tion

Dur­ing mat­ing, cop­u­la­tory plugs form in the re­pro­duc­tive tracts of fe­males that hin­der sub­se­quent mat­ings. The pres­ence of these cop­u­la­tory plugs sug­gests a polyg­y­nan­drous mat­ing sys­tem. (Car­leton and Musser, 1984)

Some ger­billine species breed year-round, and some breed sea­son­ally. Fe­males of most species are polyestrus and are able to bear mul­ti­ple lit­ters in a year. Some also ex­pe­ri­ence a post­par­tum es­trus and de­layed im­plan­ta­tion, such that a new lit­ter be­gins de­vel­op­ing as soon as the first is weaned. Ges­ta­tion pe­ri­ods, if fe­males are not lac­tat­ing, last three to four weeks, longer if lac­tat­ing. Over­all, lit­ter sizes range from 1 to 13, al­though lit­ters of 4 to 7 are much more com­mon. Young ger­bils are born com­pletely naked and blind. They begin to grow fur be­tween 8 and 13 days after birth, and are fully furred at 13 to 16 days. Eyes open about two or three weeks after birth. The young can walk quickly and hop about on all fours at about three weeks. At around one month of age, the young are weaned and in­de­pen­dent; they reach sex­ual ma­tu­rity at 10 to 16 weeks. (Demp­ster and Per­rin, 1989; Nowak, 1999)

Fe­male ger­bils brood their young until the young are about 30 days old. When brood­ing, they stand on all fours with their feet splayed out around the lit­ter. Ger­bil moth­ers are known to move their young to new nests sev­eral times for the first cou­ple of days after birth, and also to switch bur­rows be­tween lit­ters. When they leave the young in the nest to go out for­ag­ing, they some­times cover their brood with grass and sand and block up the nest en­trance. Fe­males carry their young by grip­ping them around the mid­sec­tion in their mouths. Once the young are able to move around more, moth­ers grab them by their tails and pull them near, then carry the young back to the nest. They stop re­triev­ing their young when the young are be­tween 17 and 23 days old. Moth­ers fre­quently groom their young; lick­ing the neonates' hindquar­ters to stim­u­late them to pro­duce urine and feces, which the moth­ers then con­sume. Ger­bil moth­ers groom their lit­ters until the young go off on their own; the young of some species begin groom­ing each other and their moth­ers 25 days after birth. Males of some species brood and groom their young in the same man­ner as fe­males. (Demp­ster and Per­rin, 1989; Nowak, 1999)

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

Lifes­pan/Longevity

Most ger­billines do not live longer than three or four months in the wild. In cap­tiv­ity, some ger­billines have been known to live as long as eight years. (Nowak, 1999)

Be­hav­ior

Ger­billines are ter­res­trial and most are salta­to­r­ial. Some species are ca­pa­ble of re­mark­able leaps of up to 3.5 me­ters. Other species lo­co­mote cur­so­ri­ally on all fours. Those that live in rocky habi­tats are often good climbers. For the most part, ger­billines are di­ur­nal ro­dents, but some species are noc­tur­nal, cre­pus­cu­lar, or ac­tive both day and night. Ger­billines build bur­rows, which may be sim­ple struc­tures with just one en­trance and nest cham­ber, or elab­o­rate net­works of tun­nels with mul­ti­ple en­trances and cham­bers for nest­ing, food stor­age, and ex­cre­ment. Ger­billines take dust baths to keep their silky coats in good con­di­tion.

Some ger­billine species are soli­tary, ag­gres­sive, and ter­ri­to­r­ial, with each in­di­vid­ual in­hab­it­ing its own bur­row. Other species are highly gre­gar­i­ous and form large colonies, with many in­di­vid­u­als in­hab­it­ing tun­nel net­works tens of me­ters long and two or three me­ters deep. Still oth­ers live in small fam­ily groups, and each fam­ily group de­fends its own ter­ri­tory. There is much so­cial­iz­ing among some ger­billines while they are in the nest. The pups groom one an­other, chase each other, and play-fight when they are be­tween 18 and 35 days old.

Ger­billines are mainly seden­tary, though the young may go through a no­madic pe­riod until they are able to es­tab­lish per­ma­nent home ranges, and some species mi­grate in times of drought. Ger­billines do not hi­ber­nate or aes­ti­vate, but in some areas they ex­pe­ri­ence long bouts of tor­por in the win­ter and re­main in their bur­rows liv­ing off of stored food for months at a time. (Car­leton and Musser, 1984; Demp­ster and Per­rin, 1989; Hub­bard, 1972; Nowak, 1999)

Com­mu­ni­ca­tion and Per­cep­tion

Ger­billines have large eyes and good vi­sion. They also use au­di­tory, chem­i­cal, and tac­tile cues in per­ceiv­ing their en­vi­ron­ment.

Ger­bils have a range of vo­cal­iza­tions that they use to com­mu­ni­cate with one an­other. Young ger­bils squeak when their mother en­ters the nest, grunt when they are rest­ing to­gether or climb­ing on one an­other, and they also make a click­ing noise. Adult ger­bils squeak and some­times pro­duce a high-pitched rat­tle. They also are known to drum their hind feet on the ground. Ger­billines com­mu­ni­cate with one an­other through chem­i­cal means, as well, using pheromones to sig­nal re­pro­duc­tive and so­cial sta­tus. Male ger­billines com­mu­ni­cate ter­ri­tory own­er­ship by scent-mark­ing with their large ven­tral se­ba­ceous glands. (Car­leton and Musser, 1984; Demp­ster and Per­rin, 1989; Nowak, 1999)

Food Habits

Ger­billines are pri­mar­ily her­biv­o­rous or om­niv­o­rous, con­sum­ing nuts, seeds, roots, bulbs, fruits, grasses, in­sects, bird eggs and nestlings, and even oth­ers of their own species. Ger­billines store large quan­ti­ties of plant food in their bur­rows--some­times as much as 60 kg. (Nowak, 1999)

Pre­da­tion

Ger­billines are preyed upon by var­i­ous snakes, owls, and small mam­malian car­ni­vores. To dis­cour­age preda­tors from en­ter­ing their bur­rows, some ger­billines keep the en­trances blocked with sand. Oth­ers in­cor­po­rate bolt holes into their bur­row sys­tems, into which they can make a hasty re­treat if caught out in the open. In ad­di­tion, ger­billines usu­ally have neu­tral-col­ored fur, which no doubt helps them blend in to their sandy or rocky back­ground. (Car­leton and Musser, 1984; Nowak, 1999)

  • Anti-predator Adaptations
  • cryptic

Ecosys­tem Roles

Ger­billines are pri­mary and sec­ondary con­sumers, and they are food for a num­ber of higher-level con­sumers. They are also pol­li­na­tors of cer­tain plants (John­son et al. 2001), and prob­a­bly have a role in seed dis­per­sal. Ger­billines are par­a­sitized by sev­eral flea species, such as Xenop­sylla de­bilis, Xenop­sylla hu­milis, and Xenop­sylla dif­fi­cilis. (Hub­bard, 1972; John­son, et al., 2001)

  • Ecosystem Impact
  • disperses seeds
  • pollinates

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Ger­billines, es­pe­cially Meri­ones un­guic­u­la­tus, are clean, easy to take care of, and breed read­ily in cap­tiv­ity. For these rea­sons, they are used in many lab­o­ra­to­ries for med­ical, phys­i­o­log­i­cal, and psy­cho­log­i­cal re­search. They are also pop­u­lar pets. Other ger­billine species are trapped for their skins. (Nowak, 1999)

  • Positive Impacts
  • pet trade
  • body parts are source of valuable material
  • research and education

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Some ger­billines are con­sid­ered pest an­i­mals in their na­tive ranges, be­cause they de­stroy crops, dam­age em­bank­ments and ir­ri­ga­tion sys­tems with their dig­ging, and spread bubonic plague. There is also con­cern that cap­tive ger­bils may es­cape and es­tab­lish feral pop­u­la­tions, which could out­com­pete na­tive ro­dents. (Nowak, 1999)

  • Negative Impacts
  • injures humans
    • carries human disease
  • crop pest

Con­ser­va­tion Sta­tus

Cur­rently, 35 ger­billine species are on the IUCN's Red List of Threat­ened Species. This in­cludes one crit­i­cally en­dan­gered species (Cheng's jirds, Meri­ones chengi), four en­dan­gered species (Ara­bian jirds, Meri­ones ari­mal­ius, Dahl's jirds, Meri­ones dahli, Bux­ton's jirds, Meri­ones sacra­menti, and Zarudny's jirds, Meri­ones zarud­nyi), two vul­ner­a­ble species (west­ern ger­bils, Ger­bil­lus hes­per­i­nus, and Al­lenby's ger­bils, Ger­bil­lus an­der­soni al­len­byi), one near threat­ened species (Hoogstral's ger­bils, Ger­bil­lus hoogstraali), one lower risk species (large Aden ger­bils, Ger­bil­lus poe­cilops), and 26 species that lack data. Re­search ef­forts are needed to es­tab­lish the sta­tus of those species for which lit­tle is known. (IUCN, 2004)

  • IUCN Red List [Link]
    Not Evaluated

Con­trib­u­tors

Tanya Dewey (ed­i­tor), An­i­mal Di­ver­sity Web.

Al­li­son Poor (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

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Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

chemical

uses smells or other chemicals to communicate

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

crepuscular

active at dawn and dusk

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

delayed implantation

in mammals, a condition in which a fertilized egg reaches the uterus but delays its implantation in the uterine lining, sometimes for several months.

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

folivore

an animal that mainly eats leaves.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

frugivore

an animal that mainly eats fruit

granivore

an animal that mainly eats seeds

herbivore

An animal that eats mainly plants or parts of plants.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

migratory

makes seasonal movements between breeding and wintering grounds

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

nomadic

generally wanders from place to place, usually within a well-defined range.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

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pet trade

the business of buying and selling animals for people to keep in their homes as pets.

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

saltatorial

specialized for leaping or bounding locomotion; jumps or hops.

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

solitary

lives alone

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year

Ref­er­ences

Al­ston, E. 1876. On the clas­si­fi­ca­tion of the order Glires. Pro­ceed­ings of the Zo­o­log­i­cal So­ci­ety of Lon­don: 61-98.

Car­leton, M., G. Musser. 1984. Muroid ro­dents. Pp. 289-379 in S An­der­son, J Jones Jr., eds. Or­ders and Fam­i­lies of Re­cent Mam­mals of the World. New York: John Wiley and Sons.

Cha­line, J., P. Mein, F. Pet­ter. 1977. Les grandes lignes d'une clas­si­fi­ca­tion évo­lu­tive des Muroidea. Mam­malia, 41: 245-252.

Demp­ster, E., M. Per­rin. 1989. Ma­ter­nal be­hav­ior and neona­tal de­vel­op­ment in three species of Namib Desert ro­dents. Jour­nal of Zo­ol­ogy, 218 (3): 407-420.

Eller­man, J. 1941. The Fam­i­lies and Gen­era of Liv­ing Ro­dents, vol. II. Lon­don: British Mu­seum (Nat­ural His­tory).

Hub­bard, C. 1972. Ob­ser­va­tions on the life his­to­ries and be­hav­ior of some small ro­dents from Tan­za­nia. Zo­o­log­ica Africana, 7(2): 419-449.

IUCN, 2004. "2004 IUCN Red List of Threat­ened Species" (On-line). Ac­cessed June 09, 2005 at www.​redlist.​org.

Jansa, S., M. Wek­sler. 2004. Phy­logeny of muroid ro­dents: re­la­tion­ships within and among major lin­eages as de­ter­mined by IRBP gene se­quences. Mol­e­c­u­lar Phy­lo­ge­net­ics and Evo­lu­tion, 31: 256-276.

John­son, S., A. Pauw, J. Midg­ley. 2001. Ro­dent pol­li­na­tion in the African lily Mas­so­nia de­pressa (Hy­acinthaceae). Amer­i­can Jour­nal of Botany, 88(10): 1768-1773.

Michaux, J., A. Reyes, F. Catze­flis. 2001. Evo­lu­tion­ary his­tory of the most spe­ciose mam­mals: Mol­e­c­u­lar phy­logeny of muroid ro­dents. Mol­e­c­u­lar Bi­ol­ogy and Evo­lu­tion, 18(11): 2017-2031.

Miller, G., J. Gi­d­ley. 1918. Syn­op­sis of su­per­generic groups of ro­dents. Jour­nal of the Wash­ing­ton Acad­emy of Sci­ence, 8: 431-448.

Musser, G., M. Car­leton. 1993. Fam­ily Muri­dae. Pp. 501-753 in D Wil­son, D Reeder, eds. Mam­mal Species of the World. Wash­ing­ton, D.C.: Smith­son­ian In­sti­tu­tion Press.

Musser, G., M. Car­leton. 2005. Su­per­fam­ily Muroidea. D Wil­son, D Reeder, eds. Mam­mal Species of the World. Bal­ti­more and Lon­don: The Johns Hop­kins Uni­ver­sity Press.

Nowak, R. 1999. Walker's Mam­mals of the World, vol. 2. Bal­ti­more and Lon­don: The Johns Hop­kins Uni­ver­sity Press.

Simp­son, G. 1945. The prin­ci­ples of clas­si­fi­ca­tion and a clas­si­fi­ca­tion of mam­mals. Bul­letin of the Amer­i­can Mu­seum of Nat­ural His­tory, 85: 1-350.

Sinai, P., B. Kras­nov, G. Shen­brot, I. Chosh­niak. 2003. Ecol­ogy and be­hav­iour of the lesser Egypt­ian ger­bil (Ger­bil­lus ger­bil­lus) (Ro­den­tia: Ger­bil­l­i­dae) from the Negev high­lands and Arava val­ley, Is­rael. Mam­malia, 67 (1): 1-14.

Step­pan, S., R. Ad­kins, J. An­der­son. 2004. Phy­logeny and di­ver­gence-date es­ti­mates of rapid ra­di­a­tions in muroid ro­dents based on mul­ti­ple nu­clear genes. Sys­temic Bi­ol­ogy, 53(4): 533-553.

Thomas, O. 1896. On the gen­era of ro­dents: an at­tempt to bring up to date the cur­rent arrange­ment of the order. Pro­ceed­ings of the Zo­o­log­i­cal So­ci­ety of Lon­don: 1012-1028.

Tull­berg, T. 1899. Uber das sys­tem der nageth­iere: eine phy­lo­genetis­che studie. Nova Acta Re­giae So­ci­etatis Sci­en­tiarum Up­salien­sis, 3: 1-514.