Gazella dorcas

Geographic Range

Gazella dorcas is found in the northern Ethiopian biogeographic region and the southwestern Palearctic region. These gazelles inhabit parts of northern Africa, and the Sahara and Negev deserts including: Morocco, Rio de Oro, Algeria, Tunisia, Libya, Chad, Somalia, Ethiopia and parts of Israel and Sinai in the Middle East.

• Biogeographic Regions
• palearctic palearctic
  • native native
• ethiopian ethiopian
  • native native

Habitat

Gazella dorcas is the best equipped member of the genus Gazella to inhabit dry areas. They are found in a variety of habitats: savannahs, semi-deserts, small sand dune fields, consolidated dune areas, and wadis, and are associated with a number of different plant species. High densities of G. dorcas are found in sand dune fields with high concentrations of Pancratium sickenbergeri , a preferred food.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

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

Physical Description

Gazella dorcas varies in coloration, depending on the location. They are generally pale colored and have a white underbelly with two brown stripes on either side. In the northern Sahara they are an ochre color with darker flanking stripes. Near the Red Sea, they are reddish-brown with less conspicuous, light flanking stripes. The head is darker than the rest of the body. Their horns have the most pronounced curve of members of Gazella , and within the subspecies the amount of curve in the horn varies. Horns of males are 250-280 mm long and have 20-24 rings. Female's horns are smaller (170-190 mm) and straighter with 16-18 rings. Adult males average 16.5 kg, while the females are about 12.6 kg, although average size varies among populations. They are the second smallest gazelle species .

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

• Sexual Dimorphism
• male larger
• ornamentation ornamentation

Reproduction

During the September to November mating season males will guard territory marked by their droppings. Depending on local climate, a group of G. dorcas will consist of one or two males with a harem of females or just a male-female pair. In extreme climates, where resources are scarce, they primarily associate in pairs.

• Mating System
• polygynous polygynous

In the wild, females will usually begin reproducing around age two. In captivity pregnancy can happen as early as six months of age. About 90% of females in the wild became pregnant. They give birth to only one offspring per pregnancy in almost all cases. Pregnancy lasts around six months and the fawn is born with hair and open eyes. Young spend the majority of their first two weeks curled up in the shade. Afterwards they will follow the mother around looking for solid food. Males do not seem to participate in the care of the young, except indirectly through resource defense for the group.

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

Females nurse their young for one to two minutes several times a day for around 3 months. For the first two weeks of the young gazelle's life, the mother grazes and sleeps away from the young gazelle, leaving it in a safe spot. As the young gazelle grows, they join their natal group for the first year, or longer.

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

Lifespan/Longevity

In captivity Gazella dorcas can live up to 15 years. Average lifespan in the wild is unknown and may vary by population.

Behavior

Activity patterns are determined by the severity of the climate. In hot summers these gazelles are mostly active at dawn and dusk. In milder temperatures they can be active all day. They may also become nocturnal when under predation pressure from diurnal predators. Depending on the climate, G. dorcas can travel in pairs or larger groups consisting of one or two males with a harem of up to four females and their young. Sometimes males will travel in bachelor groups of four or five.

• Key Behaviors
• cursorial
• terricolous
• diurnal diurnal
• nocturnal nocturnal
• crepuscular crepuscular
• motile motile
• nomadic nomadic
• territorial territorial
• social social
• dominance hierarchies dominance hierarchies

Home Range

Home range of a male accompanied by a small group of females and young is about 25 square kilometers.

Communication and Perception

Gazelles have an alarm call which sounds like a short bark. They also use a louder call made in cases of extreme danger or pain. Females have a low grunt to call the young and all G. dorcas can produce a long growling sound that signals annoyance. When in danger from a predator, "stotting", described in the predation section, is a common way to warn other gazelles of the predators presence.

• Communication Channels
• visual visual
• acoustic acoustic
• chemical chemical

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

Food Habits

Gazella dorcas individuals feed on the flowers, leaves, and pods of Acacia trees in many of the areas they inhabit. They also feed on fruits and leaves of a variety of bushes. In the Negev Desert, G. dorcas feeds on Madonna lilies ( Pancratium sickenbergeri ). Depending on the season, methods for obtaining food change. In summer gazelles dig holes in the sand to remove the stem and bulb of Madonna lilies. After winter rains, gazelles eat freshly sprouted leaves. Foraging techniques permit maximum energy intake with minimum energy output. Large amounts of feeding are done in small areas with high concentrations of plant life followed by long moves to other feeding areas.

• Primary Diet
• herbivore herbivore
  • folivore folivore
  • frugivore frugivore
  • granivore granivore
  • lignivore

• Plant Foods
• leaves
• roots and tubers
• wood, bark, or stems
• seeds, grains, and nuts
• fruit
• flowers

Predation

Gazella dorcas populations have many predators. Cheetahs, lions, servals, caracals, wolves, and hyaena prey on all sizes and ages. Young can be killed by smaller predators, such as foxes, eagles, and jackals. Many of these predators have been wiped out in areas where gazelles are currently found. Humans, wolves and caracal continue to be major predatory threats to these gazelles. Gazella dorcas relies chiefly on its keen eyesight to watch for predators. They have calls described in the communication section that help alert others in a herd to the presence of a predator. Skin shivering, tail twitching, and taking bouncing leaps with its head high, also called stotting, are all used to warn others of the presence of a predator.

Ecosystem Roles

Gazella dorcas , along with some other ungulates, make up the primary mode of seed dispersal for a variety of plants in the Acacia genus between the Red Sea and Israel.

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

Gazella dorcas is hunted as a food source.

• Positive Impacts
• food food

Economic Importance for Humans: Negative

Gazella dorcas is better adapted for the environment around Israel in the Negev desert than other grazing animals. They outcompete other grazers such as sheep and goats that are used for economic purposes.

Conservation Status

This species is considered threatened and in the past was classified as vulnerable by the IUCN. The ongoing threats to this species are habitat destruction and illegal hunting.

Other Comments

Gazella dorcas individuals can go their entire lives without drinking water. They can get all the water they need from the plants they eat. There is a high mortality rate among young born in captivity because of inadequate resistance to infection.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Joshua Stoolman (author), Kalamazoo College, Ann Fraser (editor, instructor), Kalamazoo College.

References

Lawes, M., R. Nanni. 1993. The density, habitat use and social organisation of dorcas Gazelles ( Gazella dorcas ) in Makhtesh Ramon, Negev Desert, Israel. Journal of Arid Environments , 24: 177-196.

Ward, D., D. Saltz. 1994. Foraging at different spacial scales: dorcas gazelles foraging for lilies in the negev desert. Ecology , 75: 48-58.

Yom-Tov, Y., H. Mendelssohn, C. Groves. 1995. Gazella dorcas. Mammalian Species , 491: 1-6.