The gerenuk is a graceful creature with a long, thin neck. This feature inspired the name "gerenuk", which means "giraffe-necked" in the Somali language. Gerenuks are a type of gazelle, with a small head in proportion to its body, but large eyes and ears. Only the males have horns at maturity. The gerenuk is medium brown on the upper back and body and lighter on its sides, and lightest in color on its belly and undersides. Its short tail is tipped with a tuft of black hair. It has long thin legs and split hooves.
Gerenuk inhabit a continuous range in north-eastern Africa, preferring lightly bushed areas and avoiding open grass lands, dense bush, or forests (Leuthold 1978, “Ecology”). There are two gerenuk subspecies. The Southern Gerenuk Litocranius walleri walleri is the smaller of the two and is found in Kenya, north-east Tanzania, southern Somalia and southern Ethiopia. (Grubb 2002).
The gerenuk is exceptionally well adapted to arid conditions and does not drink free water. In that it differs markedly from most other ungulate species, except, at least to some degree, the dikdik, the oryx, and Grant’s gazelle (Leuthold 1978, “Ecology”).
Gerenuks are exclusive browsers, feeding on tree/shrub leaves, shoots, and sometimes flowers and fruits, as well as on some vines and climbers (Leuthold 1970). The typical gerenuk photo showcases an animal gracefully standing on his hind legs to pick a green meal from a tree or a bush.
The animals are selective and prefer certain plant species over others, as well as particular growth stages of those plants (usually the youngest leaves or shoots) (Leuthold 1970). The mechanisms that determine food selectivity in ungulates are not known in full detail. There seems to be an inherited preference for particular food items, based on their smell and, to a lesser degree, taste. However, learning also plays a role. If one observes young gerenuks, one will notice that they follow their mother and imitate her. In an experiment with a young lesser kudu and a younger gerenuk, the gerenuk followed the kudu as though the latter had been his mother. He would ingest many of the same items that the kudu ate, including several that are normally rejected by wild gerenuk (Leuthold 1977).
Evergreen species become a more important component of the diet during the dry season (Leuthold 1970). Although gerenuks apparently find these plants less tasty, they are well adapted to consuming them when deciduous species are scarce, thereby gaining an energetic advantage, especially as far as seasonal movement is concerned. Indeed, unless there is a marked stratification of the vegetation, no significant seasonal shifts of the gerenuk’s home range are observed (Leuthold 1978).