Searching for new pastures, the 1500km migration of up to a million white-eared kob in southern Sudan each year rivals that of the great herds of the Serengeti in east Africa.

Subspecies
leucotis

Life span
Up to 17 years.

Statistics
Body length: 125-180cm. Shoulder height: 70-105cm. Weight: 50-120kg.

Physical description
White-eared kob have a smooth, shiny coat which ranges from golden brown to chestnut above, with the under parts bright white. Males darken with age, becoming a deep mahogany. The white-coloured facial markings include conspicuous eye rings, the insides of ears, and a throat bib. The outer sides of the legs have a vertical black stripe running down the length, while the insides are white in colour. The bushy tail is white underneath and terminates with a black tip. The S-shaped horns are found only in males, and bend sharply backwards, before curving up.

Distribution
White-eared kob are found in suitable habitat across central Africa.

Habitat
Well-watered grasslands, especially floodplains. There are particularly large numbers of these antelope in the Sudd wetland of southern Sudan.

Diet
Grasses.

Behaviour
The kob is most active in the morning and late afternoon. Adult males are territorial, although the size of their defended ranges varies depending on the habitat and population density. Their compact groups are called leks. Leks are normally 200m in diameter, with 12-15 approximately circular individual territories which measure 15-30m across. The resident male does not physically mark his area, rather he patrols its boundaries, often whistling loudly. The length of time a male may hold his territory varies from days to months. Population densities vary from 8-124 animals per square kilometre depending on the habitat. In southeastern Sudan, huge herds congregate along waterways during the dry season from November to April, at which point the density often exceeds 1,000 animals per square kilometre.

Reproduction
Sexual maturity is reached at 13 months in females and at around 18 months in males. One young is born after a gestation period of 7.5-9 months. While births may occur throughout the year, in drought-prone areas there is a peak at the end of the rains (September-December). After birth, the young lie concealed for about six weeks, after which time they follow their mothers. They are weaned after about 6-7 months.

Conservation status
K. k. leucotis is classified as a low risk, near threatened subspecies by the IUCN. Scientists fear that the civil war that has raged in southern Sudan for twenty years may have had a catastrophic effect on their numbers, but accurate figures are hard to come by.

Voice
Males whistle to declare their territory.