East African sable antelope
| East African sable antelope | ||||||||||||
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slain male East African sable antelope ( Hippotragus niger roosevelti ) in Tanzania , in what was then German East Africa , between 1906 and 1918 |
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| Scientific name | ||||||||||||
| Hippotragus niger roosevelti | ||||||||||||
| ( Heller , 1910) |
The East African sable antelope ( Hippotragus niger roosevelti ), also known as the East African sable antelope or Roosevelt antelope , is a little-known subspecies of the sable antelope ( Hippotragus niger ). Lately it is sometimes seen as a separate species.
features
The East African sable antelope has a head body length of 175 to 182 cm. The tail is 52 to 53 cm long and the shoulder height is approximately 128 cm. The hind legs are 51 to 53 cm long. The only known weight information comes from two males who weighed between 165 and 180 kg. This subspecies is significantly smaller than the other subspecies, has much shorter horns and the distance between the horn bases is smaller. The females almost always have a pale golden-red fur, in stark contrast to the almost black colored males, even if very dark females are occasionally observed.
distribution and habitat
The distribution area of the East African sable antelope is in the Shimba Hills in southeastern Kenya and the coastal hinterland of eastern Tanzania (especially in the Selous game reserve , but also in the region around Saadani and Songea ). The distribution area is therefore strongly fragmented, possibly the Usambara Mountains and the Pangani River represent migration barriers between the populations in Kenya and Tanzania. In the south, the Rufiji could form a natural border. In 1994 a full-grown male specimen was also photographed north of Voi in the Tsavo East National Park in Kenya, although this is regarded as an isolated case. Little is known about the habitat of the East African sable antelope. In Kenya, the animals prefer open grasslands, a characteristic in which they appear to be in contrast to the other subspecies. In general, however, an occurrence in Miombo forest savannas is assumed. In the Shimba Hills, the population density was around 1.4 individuals per square kilometer in the 1970s, but the number of animals has declined sharply since then.
Way of life
Social behavior
The social system of the East African sable antelope consists of herds of females and young animals, groups of bachelors and territorial bulls, as with the other sable antelopes. The herds of the East African sable antelope consist of 7 to 48 individuals, their territories are 10 to 25 km² in size and overlap by no less than 20%. The territory of a herd includes territories of two to five males, whose territories are 4 to 9 km² in size. It has been observed that herds of 8 to 10 bulls roam the areas of the Shimba Hills on their annual foray. These can only reproduce with rutting females if they are on its territory. But there are also very dominant bulls who occasionally drive away their neighbors. The social organization of a herd is very similar to the other subspecies. In a field study, the oldest, most dominant female stayed 20 meters away from other members of the herd and was much more vigilant. Sometimes two females dispute dominance, which can result in the group splitting into two smaller ones, each with their own territory.
food
Isotope analyzes of tooth enamel have shown that the diet of the East African sable antelope consists of almost 100 percent grass. Regular gnawing of bones was observed in animals in the Shimba Hills, which can last for up to an hour, and in one calf examined for more than 5 hours in a row. Possibly this serves to balance the mineral balance, since the soils in the region are poor in calcium and phosphates .
Reproduction
In contrast to the other subspecies, the mating season does not seem to be at its peak. The female has postpartum oestrus and is believed to be able to reproduce approximately every ten months. The gestation period is about 240 to 248 days. Newborn calves do not seem to hide, but rather quickly join the herd.
Taxonomy
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Internal systematics of the sable antelope according to Themudo et al. 2015
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The East African sable antelope was described by Edmund Heller in 1910 as a separate species as Ozanna roosevelti . He named it after the American President Theodore Roosevelt . The type locality were the Shimba Hills in Kenya. Today, however, it is considered a subspecies of the sable antelope ( Hippotragus niger ). However, newer systematics again assign it the rank of its own species. Molecular genetic studies show, however, that the East African sable antelope is part of the sable antelope and is more closely related to the subspecies H. n. Kirkii .
In western Tanzania, from the Wembere River south to Rungwe , there was probably another subspecies that today has largely crossed into the populations of the East African sable antelope. Outwardly it resembles this, but the DNA of some individuals resembles the giant sable antelope ( H. n. Variani ).
threat
The International Union for Conservation of Nature and Natural Resources (IUCN) does not list the East African sable antelope separately from the sable antelope. However, it is quite rare with only 100 to 200 specimens remaining in its northernmost part of its range in Kenya .
literature
- Richard D. Estes: Hippotragus niger Sable Antelope. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume VI. Pigs, Hippopotamuses, Checrotain, Giraffes, Deer and Bovids. Bloomsbury, London, 2013, pp. 556-565
- Colin Peter Groves and DM Leslie Jr .: Roosevelt's Sable Antelope Hippotragus roosevelti. In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 2: Hooved Mammals. Lynx Edicions, Barcelona 2011, ISBN 978-84-96553-77-4 , p. 686
Individual evidence
- ↑ a b c d e f Colin Peter Groves and DM Leslie Jr .: Roosevelt's Sable Antelope Hippotragus roosevelti. In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 2: Hooved Mammals. Lynx Edicions, Barcelona 2011, ISBN 978-84-96553-77-4 , p. 686
- ^ Richard A. Kock and T. Goss: Sable sightings in Tsavo East National Park. Journal of East African Natural History 84, 1995, pp. 19-24
- ↑ a b c d Richard D. Estes: Hippotragus niger Sable Antelope. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume VI. Pigs, Hippopotamuses, Checrotain, Giraffes, Deer and Bovids. Bloomsbury, London, 2013, pp. 556-565
- ↑ Matt Sponheimer, Julia A. Lee-Thorp, Darryl J. DeRutter, Jeanette M. Smith, Nikolaas J. van der Merwe, Kaye Reed, CC Grant, Linda K. Ayliff, Todd F. Robinson, Cory Heidelberger and Warren Marcus: Diets of southern African Bovidae: stable isotope evidence. Journal of Mammalogy 84 (2), 2003, pp. 417-479
- ↑ Ranka Sekulic and Richard D. Estes: A note on the bone chewing in the Sable antelope in Kenya. Mammalia 41 (4), 1977, pp. 537-539
- ↑ a b Gonçalo Espregueira Themudo, Ana C. Rufino and Paula F. Campos: Complete mitochondrial DNA sequence of the endangered giant sable antelope (Hippotragus niger variani): Insights into conservation and taxonomy. Molecular Phylogenetics and Evolution 83, 2015, pp. 242-249
- ^ Antelope Specialist Group: Hippotragus niger. The IUCN Red List of Threatened Species. Version 2014.3. ( [1] ); last accessed on May 9, 2015
Web links
- Hippotragus niger in the endangered Red List species the IUCN 2009. Posted by: Antelope Specialist Group, 1996. Accessed on May 9, 2015.