Latin Name: Aepyceros melampus
Lifespan: Up to 12 years.
Weight: Mature males 65 kg, females 40 kg.
Sexual differentiation:
The male is larger than the female and has horns.
Habitat:
Impalas are found in savannah, grassland and woodland biomes, often taking shelter under trees and in rocky areas.
Diet and Feeding:
Impala are predominantly grazers but will browse in the drier months if palatable grasses are less in abundance.
Reproduction and Territoriality:
Herding and breeding takes place in autumn. The dominant male herds as many females as possible into his territory with as many as 100 females or even more.
He defends his territory vigorously by chasing out any males he sees as a possible threat to his breeding herd, the threat being the possible loss of any sexually mature females to another male.
Bachelor herds follow the breeding herd within close proximity with eager males often breaking away to challenge the dominant male for ownership of the breeding herd.
Serious encounters between males may result in rutting which normally ends with the one or the other submitting by running away from the stronger, fitter ram.
Rutting between males may become intense with horns breaking off and rarely but not uncommon, death from piercing horns.
In a single breeding season up to 4 different males may dominate the same breeding herd at different periods.
The dominant male advertises his presence vocally by a series of vocalisations including grunting, snorting and roaring. He also scent-marks his territory by leaving fresh and regular deposits of dung on territory markers called “middens”. The number of middens will vary in number and are found throughout his territory with the more regularly marked middens found along the territory boundaries.
He also scent-marks by rubbing secretions of fluid from his face onto twigs and grasses.
The male regularly tests the reproductive status of females within the breeding herd by tasting their urine.
A small pit found in the males’ upper pallet leads to an organ known as the “Organ of Jacobson”. After licking the females urine, particles of urine are passed from the males tongue into the upper pallet pit then through to the Organ of Jacobson. This organ tests the urine and then sends a signal to the males’ brain to inform him of the reproductive status of the female.
After a successful copulation the female goes through a 7 month gestation period and gives birth to a single lamb, very rarely having twins.
Interesting Facts on the Impala:
•Females that have an excess level of testosterone have been known to grow horns. The horns however may grow disproportionately.
•A pregnant female is capable of extending her gestation period by up to 2 weeks if the start of the summer rains are late, which will result in poor grazing value and thus poor nutritional value of her milk produced.
•An impala can jump as far as 12 meters and as high as 3 meters!