Mountain forest hyrax

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Mountain forest hyrax
Systematics
Superordinate : Afrotheria
without rank: Paenungulata
Order : Schliefer (Hyracoidea)
Family : Hyrax (Procaviidae)
Genre : Tree hyrax ( Dendrohyrax )
Type : Mountain forest hyrax
Scientific name
Dendrohyrax validus
True , 1890

The mountain forest tree hyrax ( Dendrohyrax validus ), also known as the eastern tree hyrax , is a type of tree hyrax within the mammalian order of hyrax . It occurs in a strongly fragmented range in eastern Africa and inhabits the middle and high altitudes of Kilimanjaro , Meru and the Eastern Arc Mountains as well as the coastal areas of Kenya and Tanzania including some offshore islands. The habitats are composed of undisturbed forests. The mountain forest tree hybrids can sometimes reach a high population density here. Like all tree hyrax , the species is characterized by a guinea pig-like appearance without a visible tail. The animals are good climbers and spend a large part of their lives in trees. They are nocturnal, which is why they are rarely seen. They also live solitary and use tree hollows as shelter. Characteristic are the nocturnal vocalizations, which can differ significantly between the individual populations . The diet consists mainly of soft vegetable foods. The mountain forest tree hybrids were introduced scientifically in 1890. Up to four subspecies are recognized, the delimitation of which is not always clear. Sometimes the mountain forest tree hybrids are also managed within the steppe forest tree saxophones. The stock is considered endangered.

features

Habitus

The mountain forest tree hyrax is a small mammal, it reaches a head-trunk length of 47 to 58.8 cm and a body weight of 2.5 to 3 kg, there are no differences between males and females. Outwardly , the animals resemble a guinea pig , the physique is robust, a tail is not visible. The fur has a soft texture, the hair is thick and long. There is a certain variability in the color of the fur. The back is usually cinnamon brown, but it can turn darker brown to blackish towards the head. The characteristic color is created by hair with chocolate brown bases, cinnamon brown shafts and black tips. On the back there is a patch of yellowish white, erectable hair that frames a gland 20 to 40 mm in length. The underside of the body stands out lighter, the hair here also has a chocolate brown base, but turns into a yellowish brown towards the tip. The entire head is also covered with hair, only a narrow strip on the nose and the upper lip remains bare. Lighter spots appear on the side, so that the head appears grayer overall. There are dark brown areas around the ears and eyes. The ears are short and rounded, 12.5 to 15.5 mm long and covered on the inside with a tuft of yellowish white hair. Long whisker hairs can be found all over the body . The front feet consist of four, the hind feet of three toes. All toes have hoof-like nails, only the innermost toe of the hind feet has a claw. The rear foot length is 58 to 64 mm. Females have a pair of teats in the groin area.

Skull and dentition features

The skull length varies from 77.9 to 98.3 mm. The skull is clearly indented on the forehead line and slightly drawn out on the occiput . The nasal bones are rectangular in outline. The orbit is closed by the respective process of the frontal and zygomatic bones ( postorbital arch ). The interparietal bone (a skull bone between the occiput and the parietal bones ), in contrast to the steppe forest tree hyrax ( Dendrohyrax arboreus ), is never fused with the occiput. The temporal ridges are flat and wider in the rear than in the front. The crown process protrudes obliquely forwards on the lower jaw and forms a 45 ° angle to the row of teeth. Its rear edge runs parallel to the also rear edge of the ascending branch. The bit comprises a total of 34 teeth with the following tooth formula : . As with all tree snakes, the top row of premolars is roughly the same length as the top row of molars . The molars are characterized by low ( brachyodonte ) tooth crowns.

distribution

Distribution area of ​​the Bergwald Baumschliefers

The mountain forest tree hyrax is endemic to eastern Africa . Of all three representatives of the tree hyrax it has the most restricted distribution area. It is spotty distributed in mountainous regions like Kilimanjaro , Meru, and the Eastern Arc Mountains . The latter consist of different mountain ranges, the mountain forest tree hyrax occurs here in the Taita , Usambara , Udzungwa , Rubeho and Nguru mountains as well as in the Uluguru and the Pare mountains . Furthermore, the species occurs in the coastal forests from southern Kenya about 30 km north of Mombasa to Tanzania , as well as on the islands of Pemba and Zanzibar and some smaller offshore islands. It may also be present in Ethiopia . The entire distribution area currently covers no more than 3070 to 4250 km².

The preferred habitat consists of undisturbed lowland and mountain forests; the altitude ranges from sea level to high mountain areas. On Kilimanjaro, the mountain forest tree hyrax was detected in the altitude range from 1700 to 3070 m. He inhabits forests there, which existed with Ocotea usambarensis , Schefflera colkensii and Ficus thonningii . The highest population density is reached at around 2310 m. It is noticeable that the southern and western slopes are more densely populated with 23 and 13 animals per hectare, respectively , than the northern and eastern slopes, where only a maximum of 7 individuals occur on a comparable area. In the Eastern Arc Mountains, the mountain forest tree hybrids generally live at altitudes of 900 to 2000 m, but there are differences in the individual mountain ranges. The animals in the eastern Usambara Mountains are more common at altitudes of around 900 to 1300 m than at around 1500 m. The density of individuals is 10 to 14 animals per hectare in the former area, 4 to 6 in the latter area. Similar results were obtained in the Nguru Mountains, where up to 6 animals per hectare also occur at an altitude of around 1300 m. In the Pare Mountains, the elevation ranges from 1500 to 1800 m. In many areas it is not the food supply that is a limiting factor, but the number of tree hollows that can be inhabited.

Way of life

Territorial behavior

Like all tree hyrax, the mountain forest tree hyrax is secondarily adapted to a nocturnal life. This is shown, among other things, by the increased sense of smell and the intensive sound communication, eyes and ears, however, are not enlarged. The animals live mainly in trees ( arborikol ) and can climb well. They spend a large part of their daily workload above the ground. They are also solitary, several individuals together can only be found in mother-young animal groups. In the trees, the mountain forest hyrax retreats to rest in caves and openings in the trunk. Each individual lives in their own tree cavity, but it can happen that a tree with several openings is used by different animals at the same time. To defecate , the mountain forest tree hyrax rises to the ground and deposits both the excrement and the urine in easily visible places. This creates larger piles of several square meters in size, the ground and the vegetation are partly covered by a strongly smelling, asphalt-like , whitish substance that contains a lot of calcium carbonate . Sunbathing in the early morning hours is part of the comfort behavior . Similar to the retreat in tree hollows and the rather long rest periods, they support thermoregulation . In order to adapt to the sometimes harsh conditions in the high mountain areas, the mountain forest tree hybrids have developed a thick coat. Information on the size of the territory of the individual individuals is not available.

Sound communication is an important element of the social interaction among the tree slippers. The mountain forest tree hybrids utter long screams, which are often carried several hundred meters. The calls can be heard in the twilight phases from 7:00 p.m. to 9:00 p.m. and from 4:00 a.m. to 6:00 a.m. They hardly vary over the year, so it is unclear whether they are influenced by seasonal climatic cycles or moon phases. Only in foggy weather do the animals occasionally stop calling. In the entire distribution area, three different zones can be distinguished based on the call profiles. On the islands off the coast of Tanzania, knocking calls dominate with a clearly distinguishable loud and quiet phase, which are introduced by a unit of two to four high tones. Several types of calls are known of animals from the Uluguru Mountains as well as the Rubeho and Udzungwa Mountains, all located in the central section of the Eastern Arc Mountains. A monotonous sequence of five to six hacking sounds may be emitted spontaneously. Another call also consists of hacking sounds, which then change into tones that are reminiscent of table tennis balls that hit quickly. It is typical of excited animals. Two further calls, on the one hand high-pitched screams, on the other hand complex hacking sounds made up of six to twelve single and single double tones, can be heard during fights or are an expression of strong competition with a high population density . The animals in the Taita Mountains , in the Pare Mountains and in the Usambara Mountains in the northern area of ​​the Eastern Arc Mountains have an extensive sound repertoire. Typical here is a scream that is reminiscent of a choking gulp.

Despite the sometimes quite high local distribution density, the mountain forest tree hybrids are rarely sighted, which is related to the nocturnal way of life. As a rule, his calls and piles of poop indicate his presence, both of which decrease significantly in severely disturbed areas. According to investigations in largely undisturbed areas in the Udzungwa Mountains using camera traps , the species is much less apparent in the rainy season than in the dry season. It is assumed that the animals largely restrict their activities in the ground during the wet season, while this hardly affects their activities in the trees, such as their nocturnal calls.

nutrition

The mountain forest tree hyrax feeding on plants eat-driven soft plant material ( browsing ). He prefers leaves , twigs , fruits and buds . He looks for food mainly in the trees, only occasionally does an animal climb onto the ground and eat herbs or vines there. The mountain forest tree hyrax feeds mainly at night, only rarely during the day. It is noteworthy that the African violet is not consumed by the hyrax in the high areas of the Udzungwa Mountains. It increasingly grows in the nutrient-rich faeces of the animals and thus benefits from coexistence with them.

Reproduction

To date, hardly any studies have been carried out on the reproduction of the mountain forest tree slipper. There is an increased number of births in August and the mating season is likely to occur during the dry season. The gestation period is given as around 7.5 months or 220 to 240 days. As a rule, one or two young are born and are described as precocious. There is no information on the length of the suckling period, on development and sexual maturity or on life expectancy.

Predators and parasites

The most important predators make the leopard , genet , the African palm civet , the Serval , the African civet , the Crowned Eagle and the Northern Rock Python . Studies to parasites are not available.

Systematics

The mountain forest tree hyrax is a species from the genus of tree hyrax ( Dendrohyrax ). This includes two other representatives. The tree hyrax in turn belong to the family of hyrax (Procaviidae) within the order of the hyrax (Hyracoidea). The order was particularly rich in shape and variety in the Paleogene and early Neogene, with small to huge animals that showed numerous ecological adaptations and were spread over large parts of Eurasia and Africa . Today it is limited to the African continent, but also occurs with one form in the Middle East and consists of only one family with representatives the size of guinea pigs . The tree hyrax represent the most species-rich group of today's hyrax. In contrast to the other members of the Procaviidae family, they are tree-dwelling, solitary and nocturnal.

In some cases, the mountain forest tree hyrax was considered identical to the steppe forest tree hyrax ( Dendrohyrax arboreus ). As a rule, both are now considered to be separate species. The number of subspecies is not clear, four are often mentioned:

  • D. v. neumanni ( Matschie , 1893); on the islands of Zanzibar , Pemba and Tumbatu ; Back brown, back spot short (30 to 35 mm) and white to light ocher colored, belly white, feet brown and light ocher colored speckled, light spot above the eyes
  • D. v. schusteri Brauer , 1917; in the Uluguru Mountains, possibly also in the Udzungwa and Rubeho Mountains ; Head and back brown-black, back spot 55 mm long
  • D. v. terricolus Mollison , 1905; in the Taita and Usambara Mountains and in the Pare Mountains ; Head and back black-brown or chocolate-brown, back spot 55 mm long, belly white or white-yellow, fur very soft
  • D. v. validus True , 1890; on Kilimanjaro and on Meru ; Head and back chocolate brown, back spot short and light ocher-colored to light rust-colored, belly light ocher-colored, feet brown, fur very soft

In other classifications, the animals of the Eastern Arc Mountains ( D. v. Schusteri and D. v. Terricolus ) are also grouped into a subspecies and then under D. v. terricolus , sometimes the form D. v. vosseleri recognized and replaces D. v. schusteri in some areas of the central Eastern Arc Mountains. Overall, the distinction between the subspecies is unclear. In relation to the clearly different calls of the animals and the three different "sound zones" that have been differentiated so far, the species status of the populations there may be discussed. Individuals from Ethiopia, where the mountain forest hyrax was not originally known, could also represent a new subspecies or species due to some external features such as yellowish orange eyebrows and a spotted whitish yellow underside. Some researchers are therefore calling for a systematic revision of the mountain forest tree slipper.

Frederick William True

The first scientific description comes from Frederick William True from the year 1890. True had five individuals at his disposal, who had been collected by William Louis Abbott on Kilimanjaro and from the area around Taveta at the foot of the mountain in Kenya, Kilimanjaro is considered a type area of Bergwald Baumschliefers. The holotype , a fully grown male, was discovered by Abbott in June 1888. Only three years later, Paul Matschie introduced the form Procavia neumanni from the Pangani Forest on Zanzibar , based on four individuals from Oscar Neumann's collection , including a newborn baby around three days old. In his description, Matschie referred his new species to the genus of the rock hyrax ( Procavia ), but recognized that the animals are tree hyrax due to their tree-climbing lifestyle. He subsequently corrected the genus affiliation in 1895. Theodor Mollison himself collected several specimens of tree slivers in the Usambara Mountains in 1904, all of them females, several of them pregnant. A year later in his publication he highlighted their nocturnal calls from the treetops and mentioned that the animals would retire to rest in crevices in the rock. Because of the latter property, he suggested the scientific name Dendrohyrax terricola . In 1917 August Brauer introduced the subspecies Dendrohyrax terricola schusteri , the holotype of which comes from the Uluguru Mountains. In the same publication he also named Dendrohyrax terricola vosseleri from the Usambara Mountains. The animals differed from the darker representatives of D. v. terricolus , but it has been suggested that it is just a color morph. In 1934 Herbert Hahn summarized all the forms mentioned in a revision of the recent hyraxes into one species.

Threat and protection

The greatest threats to the mountain forest tree hybrids are the destruction of forests and the deterioration and fragmentation of habitats through logging and forest fires. Although individual individuals can survive in closed forest areas of around 1 km², the selective removal of large trees is problematic. This often removes important hiding places, destroys trails through the forest canopy and forces the animals to walk across the ground, exposing them to other dangers. In addition, there is the hunt for the animals, which takes place in all parts of the distribution area. It takes place because of the meat, and blankets and cloaks are made from the fur. Sometimes traps are used near the tree roots, but the animals are also slain or captured with dogs. The IUCN classifies the mountain forest tree hyrax as ( "potentially at risk" near threatened ) one (2017), until 2008 the stock as was "not at risk" ( least concern ), which at that time with the widespread and large adopted population was justified . In the following period the distribution area proved to be clearly fragmented and there was also a noticeable decline in the population. The species is present in several nature reserves, including Kilimanjaro National Park , Arusha National Park and Udzungwa Mountains National Park , as well as various reserves in the Eastern Arc Mountains and on the islands.

literature

  • Hendrik Hoeck: Family Procaviidae (Hyraxes). 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 , pp. 28–47 (p. 47)
  • Diana Roberts, Elmer Topp-Jørgensen and David Moyer: Dendrohyrax validus Eastern Tree Hyrax. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume I. Introductory Chapters and Afrotheria. Bloomsbury, London, 2013, pp. 158-161

Individual evidence

  1. ↑ a b c d e f g h i Hendrik Hoeck: Family Procaviidae (Hyraxes). 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 , pp. 28–47 (p. 47)
  2. ↑ a b c d e f g h i j k l m n o Diana Roberts, Elmer Topp-Jørgensen and David Moyer: Dendrohyrax validus Eastern Tree Hyrax. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume I. Introductory Chapters and Afrotheria. Bloomsbury, London, 2013, pp. 158-161
  3. ↑ a b c d e Herbert Hahn: The family of the Procaviidae. Zeitschrift für Mammaliankunde 9, 1934, pp. 207–358 ( [1] )
  4. ↑ a b c Norbert J. Cordeiro, Nathalie Seddon, David R. Capper, Jonathan MM Ekstrom, Kim M. Howell, Isabel S. Isherwood, Charles AM Msuya, Jonas T. Mushi, Andrew W. Perkin, Robert G. Pople and William T. Stanley: Notes on the ecology and status of some forest mammals in four Eastern Arc Mountains, Tanzania. Journal of the East Africa Natural History Society 94, 2005, pp. 175-189
  5. ↑ Francesco Rovero and Daniela W. De Luca: Checklist of mammals of the Udzungwa Mountains of Tanzania. Mammalia 71, 2007, pp. 47-55
  6. ↑ a b U. Seibt, HN Hoeck and W. Wickler: Dedrohyrax validus True, 1890 in Kenya. Journal of Mammals, 42, 1977, pp. 115-118
  7. ↑ a b c H. Hoeck, F. Rovero, N. Cordeiro, T. Butynski, A. Perkin and T. Jones: Dendrohyrax validus. The IUCN Red List of Threatened Species 2015 :. e.T136599A21288090 ( [2] ); last accessed on November 5, 2017
  8. ↑ a b c J. N. Kundaeli: Distribution of tree hyrax (Dendrohyrax validus validus True) on Mount Kilimanjaro, Tanzania. East African Wildlife Journal 14, 1976, pp. 253-264
  9. ↑ J. Elmer Topp-Jørgensen, Andrew R. Marshal, Henry Brink and Ulrik B. Pedersen: Quantifying the response of tree hyraxes (Dendrohyrax validus) to human disturbance in the Udzungwa Mountains, Tanzania. Tropical Conservation Science 1, 2008, pp. 63-74
  10. ↑ Emanuel H. Martin, Vedasto G. Ndibalema and Francesco Rovero: Does variation between dry and wet seasons affect tropical forest mammals' occupancy and detectability by camera traps? Case study from the Udzungwa Mountains, Tanzania. African Journal of Ecology 55, 2016, pp. 37-46
  11. ↑ Jehezekel Shoshani, Paulette Bloomer and Erik R. Seiffert: Family Procaviidae hyraxes. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume I. Introductory Chapters and Afrotheria. Bloomsbury, London, 2013, pp. 150-151
  12. ^ Paulette Bloomer: Genus Dendrohyrax Tree Hyraxes. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume I. Introductory Chapters and Afrotheria. Bloomsbury, London, 2013, p. 152
  13. ↑ Don E. Wilson and DeeAnn M. Reeder: Mammal Species of the World. A taxonomic and geographic Reference. Johns Hopkins University Press, 2005 ( [3] )
  14. ^ GH Swynnerton and RW Hayman: A Checklist of the Land Mammals of the Tanganyika Territory and the Zanzibar Protectorate. Journal of the East African Natural History Society 20, 1950, pp. 274-392 (p. 337)
  15. ↑ a b Herbert Hahn: From tree, bush and clip sleepers. Wittenberg, 1959, pp. 1-88
  16. ^ Frederick William True: Description of two new species of mammals from Mt. Kilima-njaro, East Africa. Proceedings of the United States National Museum 13, 1890, pp. 227-229 ( [4] )
  17. ^ Paul Matschie: About apparently new African mammals. Meeting reports of the Society of Friends of Natural Sciences in Berlin, 1893, pp. 107–114 ( [5] )
  18. ↑ Paul Matschie: The mammals of German East Africa. Berlin, 1895, pp. 1–157 (pp. 91–92) ( [6] )
  19. ^ Theodor Mollison: Dendrohyrax nova species aff. D. Neumanni. Zoologischer Anzeiger 29, 1905, pp. 417-424 ( [7] )
  20. ↑ A. Brauer: New Procaviiden. Meeting reports of the Society of Friends of Natural Sciences in Berlin, 1917, pp. 293–303 ( [8] )

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