Species Fact Profile: Gerenuk (Litocranius walleri)

Gerenuk
Litocranius walleri (Brooke, 1879)

Range: East Africa – Ethiopia, Eritrea, southern Somalia, Kenya, and northeastern Tanzania.  Historically present in eastern Egypt and northeastern Sudan as well

Habitat: Dry Grasslands, Savannahs, Scrubland, Semi-Desert, Desert

Diet: Tender young leaves.  Have been observed eating over 80 species, with a preference for Acacia

Social Grouping: Males solitary and territorial.  Females form small herds (10-12)

Reproduction:  Females breed every 1-2 years, breeding can occur year round. Usually a single calf born after a gestation of 165 days.  Young are precocial and can walk within minutes.  Females wean at 1 year, males at 1.5 years (and usually stay with mother until age 2).  Sexually mature at time of independence, but males don’t usually breed until they are able to establish a territory at about 3-4 years old

Lifespan: 10-15 Years

      Conservation Status: IUCN Near Threatened

•       Body length 140-160 centimeters, 90-105 centimeters at the shoulder, tail length 22-25 centimeters, weight 29-58 kilograms.  Recognizable by very long, slender neck and legs and a long, narrow head.  Sexes are of similar size, but males are more muscled, making them weigh more.  Males alone have curved, ridged, lyre-shaped horns 25-44 centimeters long
•       Coat is short, fine, glossy, pale tawny brown fading to a white on the breast, underbelly, and the inside of the legs, with darker patches on the knees of the forelegs and the end of the tail.  Additional dark patches around the eyes, growing paler around the edges before fading to white
•          Vocalizations include an alarm buzz, an irritation whistle, an aggressive grumble, a loud bleat for danger, and a softer bleat used by mothers to call to their calves
•       Courtship display consists of male displaying his horns and neck in a sideways pose while the female holds her nose in the air and lays back her ears; the male will then rub the female with his preorbital gland and follow her, occasionally kicking at her.  Male samples the urine to determine receptiveness.  
•       Males mark trees and shrubs with their preorbital glands to establish territories of 300-850 acres.  Younger males are run off, females are allowed to come and go (other dominant males are also allowed entry).  Young males often form bachelor herds until they are able to establish their own territories.  
•       Able to stand on their hind legs (due to strong hind legs, wedge-shaped hooves, and specialized lumbar vertebrae) to obtain leaves that are out of reach of other antelope, with a standing height of over 2 meters.  Able to use their front legs to hook and pull down branches 2.5 meters high.  Long tongue and mobile lips help select small leaves, while lashes around eyes protect eyes from thorn scratches.  
•       Does not drink standing water, instead obtaining moisture from succulent plants
•       Mostly active by day, but will rest in the shade during the hottest part of the day
•       Predators include cheetah, leopard, lion, hyenas, and African wild dogs, with calves vulnerable to large captors, caracals, and other mid-sized predators.  Not very fast runners, primarily depend on remaining still and unseen to avoid predators.  Horns are mainly used in territorial disputes between males rather than in defense.
•       Common name from Somali name for the animal, garanuug (“giraffe-necked”).  Sometimes called “giraffe gazelle”
•      Two subspecies – the northern (L. w. sclateri) and southern (nominate).  The boundary between the two is not clearly defined.  Northern subspecies is slightly larger 
• ·        Degradation of habitat for other antelope species can actually lead to improved gerenuk habitat, as they prefer the sort of scrublands that can arise from overgrazing, but excessive desertification (brought about by clearing of brush for firewood, charcoal can harm them).  Much of range is too arid to support intensive agriculture
• ·        Other causes of decline can include hunting (exacerbated by wars), drought, and introduced disease from domestic livestock, such as rinderpest.
• ·     Depicted in carvings from Ancient Egypt, hinting as past range extension to the north