Both sexes of gerenuk are of similar size, but the males are more muscular than females causing them to outweigh them.
The gerenuk population has been estimated at 24,000, based on aerial counts. That figure has been revised to 95,000 to account for under-counting bias in aerial surveys.
The species is difficult to census both from the ground and especially from the air, due to its often dense bush habitats, small group size and cryptic coloration.
Density estimates range from a maximum of 0.2/km² on aerial surveys to 1.0/km² from road counts and up to 8.0/km² in particularly favorable habitats, such as Samburu G.R. in Kenya. The largest surviving populations occur in south-western Ethiopia and the northern and eastern rangelands of Kenya.
Population trend may be generally stable in protected areas, with a few exceptions such as the declining population of Tsavo National Park, and slowly decreasing elsewhere. It’s been suggested a 50% decline in Kenya since 1970. In Tanzania, Gerenuks remain common in the Lake Natron area and fairly common in West Kilimanjaro, but have declined in the Makame depression in recent years because of over-hunting.