Litocranius walleri

Geographic Range

Litocranius walleri inhabits the dry brushy region of east Africa from the Serengeti plain of Tanzania north along the coast through Kenya, Ethiopia, Eritrea, and into southern Somalia. The species was once found in eastern Egypt and northeastern Sudan as well.

• Biogeographic Regions
• ethiopian ethiopian
  • native native

Habitat

The habitat that Litocranius walleri occupies varies from the treeless plains of Tanzania in the southern reaches of its range to the dry high deserts of Kenya. They are adaptable and do well in a variety of habitats, provided there is a good supply of succulent plants.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

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

Physical Description

The long neck and long, thin legs of gerenuks are their defining features; these make them one of the world's most easily recognized antelopes. The coat is of a short, fine, glossy hair that is evenly distributed over the whole body. The pelage is a pale tawny brown with white along the breast, underbelly, and inner legs. There are small, dark patches of fur on the knees of the forelegs and at the end of the tail. The head is long and narrow with medium-sized ears, and the cheek teeth and masseter muscle are reduced. On the head there is a dark patch around the eyes that pales as it goes outward until it forms a white rim. Only males of this species have head ornamentation in the form of scimitar shaped horns ranging from 25 to 44 centimeters in length. Both sexes of L. walleri are of similar size but the males are more muscular than females causing them to outweigh them. Mass ranges from 29 to 58 kg, total body length from 140 to 160 cm, and tail length from 220 to 350 mm.

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

• Sexual Dimorphism
• ornamentation ornamentation

Reproduction

The mating ritual of Litocranius walleri is complex. When a male encounters a potential mate the female will raise her nose into the air and pull her ears close to the head as a sign of defensiveness, meanwhile the male displays his horns and neck in a sideways pose. If the female is receptive then the male will mark the female on the thigh with the contents of his preorbital gland and contiue to follow her around, a form of mate guarding. As the male follows the female he continually uses his forelegs to kick the female in her thigh region. When the female atempts to urinate the male performs the flehmen test or lip curl test in which he samples her urine. Once the female comes into estrous the male will notice the difference in the females urine and mating will begin. Males will attempt to mate with as many females as they can. (Macdonald, 1984)

• Mating System
• polygynous polygynous

Gerenuk females breed every one to two years, depending on the sex of their previous year's offspring. Males are dependent on their mothers for longer than are females. Reproduction and births occur throughout the year and may depend on the quality of available nutrition. Females give birth to usually one young after a gestation period of about 165 days.

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

Female Litocranius walleri usually give birth to one young, rarely two. The young are precocial and begin to walk within minutes of birth. The female continues to look after her young until she weans them. Young females get weaned when they reach one year of age but male offspring are not weaned until they reach at least one and a half years old and stay with their mothers until after they are two.

• Parental Investment
• altricial altricial
• female parental care female parental care
• post-independence association with parents

Lifespan/Longevity

The average life span of female Litocranius walleri is slightly longer than males. Their lifespan in the wild averages 10 - 12 years.

Behavior

Litocranius walleri have never been an abundant species. At Tsavo National Park in Kenya, where L. walleri is protected and enjoys good habitat, researchers have concluded that L. walleri makes up less then .5% of the total biomass of hoofed mammals in the park. Because they do not form large populations and their food is of limited supply they exhibit strange social interactions. Males are solitary and very territorial, they only associate with females during the mating season or when they are young. Dominant males establish territories by marking trees and shrubs with their preorbital gland. Other dominant males will enter another's territory without any aggression or defensiveness being displayed but a young male without its own territory will be run off if it enters a dominant male's territory. The size of a males territory can range from 300 to 850 acres and can support several indivduals. Females form small bands of up to about 10 individuals, usualy related adults with young. These groups of females and young roam freely throughout male territories. Young males that have just been weaned often form bachelor herds that roam nomadically until they become mature enough to establish their own territories and breed.

Gerenuke are primarily active during the day.

• Key Behaviors
• terricolous
• diurnal diurnal
• motile motile
• nomadic nomadic
• sedentary sedentary
• solitary solitary
• territorial territorial
• social social

Communication and Perception

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

• Other Communication Modes
• pheromones pheromones
• scent marks scent marks

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

Food Habits

Litocranius walleri is well adapted for obtaining forage from their arid habitats. Their long necks, long legs, and the ability to stand on their hind legs allows L. walleri to obtain tree leaves that are out of reach for most other antelope species. This permits gerenuks to be selective in the foods they eat and to be efficient browsers of herbaceous plants. Over 80 different species of plants have been found in a single individuals stomach. L. walleri does not drink free standing water, they instead rely on water taken in when they eat succulent plants.

• Primary Diet
• herbivore herbivore
  • folivore folivore

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

Predation

Several anti-predator adaptations have evolved in Litocranius walleri for their survival both while they are juveniles and as adults. Young L. walleri remain motionless while hiding in the bushes and tall grasses not far from their mothers during the day when the mother is feeding. As adults they show an adaptation that is more common to forest dwelling antelopes than to desert-adapted ones, they freeze at the aproach of danger. They are preyed on by a diverse set of large predators found throughout their range.

Ecosystem Roles

Although rare, gerenuk contribute to nutrient cycling in the ecosystems in which they live through their foraging activity. They also act as prey species for large predators.

Economic Importance for Humans: Positive

Litocranius walleri has been a game animal in Africa for over 200 years. Although they are limited in supply for hunters and have a limited range, they continue to be hunted for trophies and for bush meat. In the expanding world of photosafaries and parks in Africa L. walleri will become a regular subject for this endeavor. Unfortunately L. walleri doesn't do well in captivity and has rarely been bred in zoos.

• Positive Impacts
• food food
• ecotourism ecotourism

Economic Importance for Humans: Negative

There are no adverse effects of L. walleri on humans.

Conservation Status

Litocranius walleri is a game animal, even though its not very common, and as a game animal it is protected in most of its range in the form of tags or permits. There are many parks offering sanctuary for them within their range and many biologists and game managers studying them so they are not considered to be at significant risk currently.

Additional Links

Encyclopedia of Life

Contributors

Jamie Payne (author), Humboldt State University, Brian Arbogast (editor), Humboldt State University.

References

Fiorenza, P. 1983. Encyclopedia of Big Game Animals of Africa . New York City, New York, USA: Larousse and Co. Inc..

Macdonald, D. 1984. The Encyclopedia of Mammals . New York NY: Facts on File Publications.

Parker, S. 1990. Grizimek's Encyclopidia of Mammals vol 5 . New York NY: McGraw-Hill Publishing Company.