Black wildebeest
Features necessary for defending a territory, such as the horns and broad-based skull of the modern black wildebeest, have been found in their fossil ancestors. The earliest known fossil remains are in sedimentary rock in Cornelia in the Orange Free State and date back about 800,000 years. Fossils have also been reported from the Vaal River deposits, though whether or not they are as ancient as those found in Cornelia is unclear. Horns of the black wildebeest have been found in sand dunes near Hermanus in South Africa. This is far beyond the recorded range of the species and it has been suggested that these animals may have migrated to that region from the Karoo.
Black wildebeest
Both sexes have strong horns that curve forward, resembling hooks, which are up to long. The horns have a broad base in mature males, and are flattened to form a protective shield. In females, the horns are both shorter and narrower. They become fully developed in females in the third year, while horns are fully grown in males at age of four or five. The black wildebeest normally has 13 thoracic vertebrae, though specimens with 14 have been reported, and this species shows a tendency for the thoracic region to become elongated. The scent glands secrete a glutinous substance in front of the eyes, under the hair tufts, and on the forefeet. Females have two teats. Apart from the difference in the appearance of the tail, the two species of wildebeest also differ in size and colour, with the black being smaller and darker than the blue.