Damaliscus lunatus is a large African antelope of the genus Damaliscus and subfamily Alcelaphinae in the family Bovidae, with a number of recognised geographic subspecies. Some authorities have split the different populations of the species into different species,Damaliscus lunatus, MSW3 although this is seen as controversial. Common names include topi, sassaby (formerly also sassayby), tiang and tsessebe.
Etymology
The word tope or topi is Swahili, and was first recorded by the German explorer Gustav Fischer on the ancient city island of Lamu off the Kenyan coast. Other names recorded in East Africa by various German explorers were mhili in Kisukuma and jimäla in Kinyamwezi. The Luganda name was simäla according to Neumann, or nemira according to Lugard.
Taxonomy The first thing published about this antelope was the afore-mentioned painting of a young male sassayby by Daniell from 1820, but the first scientific description was by William John Burchell in 1824. In 1812 hunters attached to Burchell's expedition shot a female animal in what is now Free State, in what is thought to be the southernmost part of its range. Burchell named it the "crescent-horned antelope", Antilope lunata. Burchell had the horns and frontlet sent to London, this is now the type specimen. Charles Hamilton Smith was the first to equate the sassayby with Antilope lunata in the 1827 section on ruminants in the English translation of George Cuvier's Le Règne Animal.
An 1822–1824 British expedition across the Sahara to the ancient kingdom of Bornu, returned with single set of horns of an antelope known in the language of that land as a korrigum. In 1836 these horns were classified as a new species.
Until the early 2000s the generally accepted taxonomic interpretation of the different geographic populations of topi antelopes was that of Ansell in 1972, who recognised five subspecies. In 2003 Fenton Cotterill published a paper advocating splitting the southern, nominate subspecies into two independent species under something he invented called the 'Recognition Species Concept', and regarding the northern four subspecies as a different, provisional species (Damaliscus korrigum). In the 2005 Mammal Species of the World Grubb accepted Cotterill's interpretation in full, splitting the topi into three species: a southern, northern and Cotterill's new Bangweulu species (D. superstes). In 2006 Macdonald considered the topi to be a single species with six subspecies, subsuming the Bangweulu (see map). The IUCN SSC Antelope Specialist Group followed this interpretation in 2008. In the 2011 book Ungulate Taxonomy, Colin Groves and Grubb went even further and split the topi into nine species. They used what they called the "diagnostic phylogenetic species concept" to split this species and many others based on small qualitative physical differences between different geographic populations, based on small sample sets, and often without publishing any research supporting their positions. This proved controversial among mammalogists. Despite the stipulations Groves and Grubb set out with regards to how their species concept should discriminate between species, the skeletal morphometrics they publish show that the four East African topi species cannot be distinguished from each other, as the two taxa in North and West Africa cannot. Barring that, the main criteria for recognising species in these two groups is the authors' opinion on the hair colour of a limited number of specimen skins, with the different species being (ranges in) various shades of brown. The rapid increase in recognised species which could not reliably told apart was termed "taxonomic inflation" by some.
As of 2021 the ASM Mammal Diversity Database thus decided to reject the Groves and Grubb taxonomic interpretation of the topi in its entirety, and in this case also reject the 2005 Mammal Species of the World, essentially reverting to the 1972 Ansell view with the addition of superstes as a synonym of D. lunatus.
Topi To the north of Lake Bangweulu in Zambia, across the border and beyond the rift valley, above the north shore of Lake Rukwa in Tanzania, the topi subspecies that occurs there is generally recognised as Damaliscus lunatus jimela, and usually just called a 'topi'. This subspecies has horns with a lyrate profile.
Description
Adult topi are 150 to 230 cm in length. They are quite large animals, with males weighing 137 kg and females weighing 120 kg, on average. Their horns range from 37 cm for females to 40 cm for males. For males, horn size plays an important role in territory defence and mate attraction, although horn size is not positively correlated with territorial factors of mate selection. Their bodies are chestnut brown or reddish brown. They have a mask-like dark colouration on the face and their tail tufts are black; the upper forelimbs and thighs have greyish, dark purple or bluish-black-coloured patches. Their hindlimbs are brownish-yellow to yellow and their bellies are white. In the wild, topi usually live a maximum of 15 years, but in general, their average lifespan is much less.
Topi resemble hartebeest but have a darker colouration and lack sharply angled horns. They have elongated heads, and a distinct hump at the base of the neck. Their horns are ringed and lyrate-shaped. Their coats are made of short, shiny hairs.Kingdon, J. (1979). East African Mammals: An Atlas of Evolution in Africa, Volume 3, Part. D: Bovids. University Chicago Press, Chicago, pp. 485–501 They range in mass from . Head-and-body length can range from and the tail measures . They are a tall species, ranging in height from at the shoulder.Burnie D and Wilson DE (Eds.) 2005. Animal: The Definitive Visual Guide to the World's Wildlife. DK Adult Topi videos, photos and facts – Damaliscus lunatus . ARKive. Retrieved on 2013-01-16. Males tend to be larger and darker than females. Topi also have preorbital glands that secrete clear oil and the front legs have hoof glands.
Characteristic of this antelope species is the groaning sound it makes as it dies.
Topi spoor is very similar to that of oryx and hartebeest. The tracks are about 8 cm in length, the two impressed hooves are narrow and point inward distally, and the base of the hooves are bulbous and more deeply indented into the soil than the rest of the track.
Tsessebe The most significant difference between the tsessebe, the southernmost subspecies, and the other topi subspecies is the incline of the horns, with the tsessebe having horns which are placed further apart from each other as one moves distally. This has the effect of the space between them having a more lunate profile when seen from a certain angle, as opposed to lyrate, more like that of a hartebeest. Tsessebe populations show variation as one moves from South Africa to Botswana, with southerly populations having on average the lightest pelage colour, smallest size and the least robust horns. Common tsessebe do not differ significantly from the Bangweulu tsessebe, the northernmost population, but in general the populations from that part of Zambia are on average the darkest-coloured and have the most robust horns, although differences are slight and individuals in both populations show variation in these characteristics which almost completely overlap each other.
Distribution The topi has a long but patchy distribution in Southern, East and West Africa it prefers certain grasslands in arid and savanna biomes. Human hunting and habitat modification have further isolated the subpopulations. Topi are usually either numerous or absent in an area. Scattered populations do not last long and either increase or die off. The health of topis in a population depends on access to green vegetation. Herds of topi migrate between pastures. A large migration is in the Serengeti, where they join the wildebeests, zebras and gazelles.
Topi herds can take the form of "perennially sedentary-dispersion", "perennially mobile-aggregated" or something in between. This depends on the habitat and ecology of the areas they are in. Males establish territories that attract herds of females with their offspring. Depending on the size of the patches, territories can be as large as 4 km2 and sometimes border each other. In more densely populated areas, like those of Queen Elizabeth National Park in Uganda, topis move across the plain and set up territories during resting periods.
Ecology
Habitat Topi are primarily found in grasslands, treeless open plains, and lightly wooded savannas. They prefer flat lowlands but they are also occasionally found in rolling uplands (for example in Rwanda), and are very rarely seen at higher altitudes than 1,500 m above sea level. In ecotone habitats between woodlands and open grasslands, they stay along the edge using the shade in hot weather. Topi use vantage points, such as termite mounds, to get a good look at their surroundings.
Population studies appear to show that, relative to many of the other, somewhat more charismatic antelopes, these animals are habitat specialists, with a strong preference for seasonally dry grasslands. In Botswana, they spend most of their time in open habitats, primarily grassland, but will retreat to mopane woodland during the rainy season.
Diet Topi are grazing herbivores, their diet is almost exclusively grass. The topi is a selective feeder and uses its elongated muzzle and flexible lips to forage for the youngest blades of grass. Topi are not as capable as other grazers at feeding from short sward, and during the rainy season avoid both long mature grass and very short pasture, whereas in the dry season they move to any area with the most grass. When they have access to enough green vegetation, topi usually do not need to drink. They drink more when relying on dry grass.
Topi found in the Serengeti usually feed in the morning between 8:00 and 9:00 am and in the afternoon after 4:00 pm. The periods before and after feeding are spent resting and digesting or watering during dry seasons. Topi can travel up to five kilometres to reach a viable water source. To avoid encounters with territorial males or females, topi usually travel along territorial borders, though it leaves them open to attacks by lions and leopards.
Predators Predators of topi include lions, cheetahs, african wild dogs and spotted hyenas, with jackals being predators of newborns. They are especially targeted by hyenas. Nevertheless, topi tend to have a low predation rate when other species are present.
Behaviour Topi declare their territory through a variety of behaviours. Territorial behaviour includes moving in an erect posture, high-stepping, defecating in a crouch stance, ground-horning, mud packing, shoulder-wiping and grunting.
The most important aggressive display of territorial dominance is in the horning of the ground. Another far more curious form of territory marking is through the anointing of their foreheads and horns with secretions from glands near their eyes. Topi accomplish this by inserting grass stems into their preorbital glands to coat them with secretion, then waving it around, letting the secretions fall onto their heads and horns. This process is not as commonly seen as ground-horning, nor is its purpose as well known. When the resident male of a territory is absent, the dominant female may assume his behaviours, defending against outside topis of either sex using the rocking canter and performing the high-stepping display.