Rainforest Hyrax

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Rainforest Hyrax
Rainforest tree hyrax (Dendrohyrax dorsalis)

Rainforest tree hyrax ( Dendrohyrax dorsalis )

Systematics
Superordinate : Afrotheria
without rank: Paenungulata
Order : Schliefer (Hyracoidea)
Family : Hyrax (Procaviidae)
Genre : Tree hyrax ( Dendrohyrax )
Type : Rainforest Hyrax
Scientific name
Dendrohyrax dorsalis
( Fraser , 1852)

The rainforest tree hyrax ( Dendrohyrax dorsalis ), also called common tree hyrax or western tree hyrax , is a type of tree hyrax within the mammal order of the hyrax . Outwardly, it is reminiscent of guinea pigs . It is characterized by a coarse, but often not always dark colored fur and has a noticeable light spot on the back and chin. The tail remains hidden in the fur. The distribution area includes western and central Africa . Tropical rainforests and humid savannah landscapes in the lowlands serve as habitats, and in some cases forests in higher mountain regions. There the animals mostly stay in the branches of the trees, where they can climb nimbly and look for tree hollows for protection. Since they are rarely seen as a result, many aspects of their behavior are unknown. As a rule, they live solitary and territorial. They are nocturnal; their loud call, which can be heard late in the evening and early in the morning, is typical. The diet consists of soft vegetable foods. The mating probably takes place all year round, one or two precocious young are born. The species was scientifically introduced in 1852. Sometimes a distinction is made between up to six subspecies, but their separation from one another is not always clear. The rainforest tree slipper population is considered to be safe.

features

Habitus

The rainforest tree hyrax reaches a head-trunk length of 44 to 57 cm and a body weight of 1.85 to 4.5 kg. Outwardly it resembles a guinea pig with its compact physique , but it is larger. The tail is not visible because it is 10 to 30 mm long and hidden in the fur. The fur is dark brown to black in color, and is interspersed with lighter, yellowish hairs, but there are also lighter individuals overall.Generally, it has a coarser texture than that of the steppe forest tree slipper ( Dendrohyrax arboreus ), and the hairs are also shorter . In addition, however, longer whiskers appear all over the body. On the back there is a noticeable yellowish-white spot 42 to 72 mm long. This surrounds a bare gland . The ears are short and round with a length of 21 to 30 mm. White hairs can be formed on the tips. The nose is hairless, and there is a characteristic white spot on the chin, both of which are the rainforest tree hyrax from other tree snakes. The hands have four rays and the feet three rays. They have hoof-like nails. As with all snakes, the inner toe of the rear foot, which is equipped with a curved claw, is an exception. The rear foot length is 70 to 90 mm, the balls of the feet are black. Females have a pair of teats in the groin area.

Skull and dentition features

The length of the skull varies from 92 to 110 mm, the width at the zygomatic arches from 46 to 61 mm. The skull becomes 28 to 35 mm high and 30 to 38 mm wide. In general, the skull looks massive. The temporal ridges are broad and sharply demarcated, somewhat flatter at the apex. The interparietal bone (a skull bone between the occiput and the parietal bones ) does not grow together with the occiput. The postorbital arch is closed. The dentition is composed of 34 teeth, the tooth formula is also given. The lower incisors are flat and three-pointed ( tricuspid or trifid ), the upper incisors resemble a canine ( caniniform ). In relation to the posterior dentition, there is a diastema 14 to 20 mm in length in the upper jaw . The premolars are similar to the molars . The crowns of the rear teeth are low ( brachyodont ). The upper row of premolars is roughly the same length as the row of molars, corresponding to the other tree snakes.

distribution

Distribution area of ​​the rainforest tree slipper

The distribution area of ​​the rainforest tree sliver covers parts of west and central Africa from Sierra Leone to the south of South Sudan as well as the north of Uganda and southwards from the northeast of the Democratic Republic of the Congo to the north of Angola . In addition, the species is documented on the island of Bioko in the Gulf of Guinea . West of Sierra Leone there is hardly any evidence of the rainforest tree slipper, even if the original distribution information reached as far as Gambia . In the transition from the 20th to the 21st century, a population could be observed in northeastern Guinea . There is also a gap in evidence in Ghana east of the Volta and in Benin . The animals prefer moist forests and savannah areas in the lowlands and highlands around 1500 m as their habitat, but they can also be found in the mountains up to heights of 3500 m. In the high mountain areas, the rainforest tree hybrids also use rocky landscapes as habitats . Occasionally it is seen in degraded forests. Little information is available about population density. According to estimates from Taï National Park in Ivory Coast , there are one to two individuals per square kilometer. The assumptions are based on the frequency of the animals' individual nocturnal cries.

Way of life

Territorial behavior

The rainforest tree hyrax lives mainly in trees ( arborikol ). Its feet are flexible and rotatable, the handle is firm. This allows him to climb tree trunks with a diameter of up to 50 cm. Animals were observed climbing lianas , and captured individuals also climbed door frames. When climbing, they either grip the branches with their back feet or with their back and front feet. They are also able to turn the trunk and climb down head first. In this position, the hind feet hold the weight. Usually the movements are slow. Despite the lack of claws, the rainforest tree hyrax navigates safely in the branches. It is believed that the species is secondarily adapted to tree life due to its physique. Fast movements up to a gallop are also possible on the ground.

The rainforest tree hyrax is usually nocturnal. During the day he spends in tree hollows, which he leaves shortly after sunset. Its predominant activities take place in the treetops. Occasionally, however, it rises to the ground. There he deposits feces in certain latrines . In the lama forest area in southern Benin , the latrines are often associated with trees of the genus Dialium from the carob family . It is unclear whether the animals also use them as food or seek shelter in their tree hollows.

Like the other tree hyrax, the rainforest tree hyrax is solitary. Groups of two to three individuals are seldom sighted, mostly mother animals with their young. The individual individuals live territorially and maintain territories that are relatively small. Those of the males overlap with those of the females. The males defend their territories. Sometimes the animals rub their back glands on various objects. This could be a marking behavior, it may also serve to differentiate between individuals. In captivity, animals often behave aggressively and bitingly towards other species. However, they also clean each other, often on the face and neck. The lower incisors and the cleaning claw of the rear foot are used for grooming . The rear foot moves very quickly when scratching

The calls of the rainforest tree slipper are very characteristic. They can be heard during the evening and early in the morning. The call times differ slightly from region to region, in the eastern Congo Basin they can be heard from 8 p.m. to 10 p.m. and from 4 a.m. to 5 a.m., in Benin between 7.30 p.m. and midnight and from 3 a.m. to 6 a.m. A similar bimodal activity is also known from the other tree snakes. The individual calls are reminiscent of “honking” or “excruciatingly repeated screeching” and last up to five minutes, repeated several times for up to half an hour. They consist of a series of 22 to 42, sometimes up to 90 screams, which are very long and increase in intensity until they reach their climax towards the end. They are introduced by very weak, barely perceptible calls. There is some variation in the intensity and frequency of calls over the year. Both male and female animals call at night, the latter mostly when they have no partner. The animals usually always go to the same places. Sometimes calls also occur during the day, which then usually come from frightened animals. Frightened animals give a pig-like grunt.

nutrition

The main food of the rainforest tree sliver is plants. It specializes in soft foods such as fruits , twigs , buds , bark and leaves ( browsing ). In captivity, the animals consumed striped ferns, among other things . They look for the majority of their food in the trees. Occasionally, however, they also come to the ground to eat. When eating, the rainforest tree hyrax holds its head to the side, the food is crushed with the molars by horizontal chewing movements. He seldom uses his front feet to manipulate food.

Reproduction

Reproduction is not seasonal, but there is an increased birth rate during the dry season. In Gabon and Cameroon , young animals were observed from March to April, in the east and south of the Democratic Republic of the Congo from May to August. Shortly before mating, females secrete an oily secretion that smells of cinnamon from their back gland. The gestation period is eight months. One or two young animals are born that weigh around 380 g and reach around 16 cm in length. Other weights are 180 to 220 g. The young are precocious and fully hairy, they grow continuously, so that they weigh around 810 g after two months and around 1300 g after five. They are fully grown after 200 days at the latest. So far, little research has been done into the mother-young ratio during rearing. There is also no information about life expectancy in the wild, some captured animals lived in human care for up to five and a half years. It is believed that they are about as old as the steppe forest tree hyrax .

Predators and parasites

As predators , inter alia, is Leopard detected, but the Regenwald.Baumschliefer takes a reported in National Park Tai only a small part in the food spectrum of the major cat a (about 1.4% in the analyzed 210 Kotresten ). Other carnivores are eagle owls , Bonelli's eagles and crowned eagles . The proportion of the latter is also rather low. In addition, it has been observed in Guinea that chimpanzees occasionally catch, play with and kill, but not eat, individual individuals. Threatened or alarmed animals erect the hair of their light back spot, and frequent licking of the lips was also observed.

Internal parasites mostly form roundworms , for example from the genera Crossophorus , Libyostrongylus and Theileriana . In addition, ticks attack the tree hyrax , including representatives of the Hyracoptes genus .

Systematics

The rain forest tree Hyraxes is a kind from the genus of the tree hyrax ( Dendrohyrax ). Two other species are currently included in this. The tree hyrax in turn belong to the family of hyrax (Procaviidae) within the order of the hyrax (Hyracoidea). The order was particularly characterized in the Paleogene and the early Neogene by its wealth of forms and variants. There were small and huge representatives who showed the most diverse ecological adaptations. Their distribution reached over large parts of Eurasia and Africa . Today's forms of hyrax are animals the size of guinea pigs . They are largely restricted to the African continent, only one form is also common in the Near East. The tree hyrax represent the most species-rich group. In contrast to the other members of the Procaviidae family, they live in trees and are solitary and nocturnal.

Graphic representation of the subspecies D. d. emini as a light variant, from Thomas' description in 1887

There are several subspecies of the rainforest tree slipper:

  • D. d. dorsalis ( Fraser , 1852); Bioko Island ; Head and back black, the edge of the ears black to yellow-black, outside of the ears dark yellow-brown, back spot 110 mm long and pure white with 90 mm long hair, belly light brown to ocher-colored, feet black
  • D. d. emini Thomas , 1887; in the north and east of the Democratic Republic of the Congo ; Head cloudy brown, back light, the back spot almost disappears in the light color, belly dirty white or isabel colored, feet brown and white speckled
  • D. d. latrator ( Thomas , 1910); in the central Democratic Republic of the Congo; similar to D. d. emini
  • D. d. marmotus ( Thomas , 1901); Uganda , body dark, sides lighter, back spot 76 mm long and white, fur generally softer
  • D. d. nigricans ( Peters , 1879); from Nigeria to Angola ; Head black, as well as a broad stripe on the back, sides lighter, back spot 30 to 110 mm long and white, belly and sides of the body, feet black
  • D. d. sylvestris ( Temminck , 1853); from Sierra Leone to Nigeria ; Head brown, back black, sides, belly and legs brown, back spot appears as a narrow white stripe

Sometimes D. d. latrator as identical to D. d. emini . Information on the exact distribution of the subspecies is so far sparse. The rainforest tree hyrax has also been found in South Sudan and the Central African Republic , but it is not clear which subspecies the animals belong to there. In general, the various subspecies have so far been difficult to separate spatially from one another. One possibility could be to differentiate them according to their calls, which clearly differ between the individual populations . Sometimes the differences are so great that certain individuals can be overheard. It is possible that there is also another species in western Nigeria and Benin , as the animals there have a reputation that differs from that of the other rainforest tree slippers with their "horn-like" sounds. This begins with a squeak, then turns into a rattling sound and ends staccato-like without increasing. Museum specimens from the region also have a varying skull anatomy with a shorter and wider rostrum and larger openings in the upper jaw.

Graphic representation of the rainforest tree sleeper from Fraser's first description in 1852

The rainforest tree hyrax received its first scientific description by Louis Fraser under the name Hyrax dorsalis . Fraser's introduction to species is based on a male individual from the island of Bioko , which forms the type locality. In the short essay, Fraser particularly emphasizes the coarse fur, the nocturnal way of life and the animals' characteristic calls. He also added a graphic representation. The date of publication of the article is often given as 1855, but it appeared as early as 1852. John Edward Gray referred Hyrax dorsalis in his reorganization of the hyrax in 1868 to the newly created genus Dendrohyrax . In the year after Fraser's first description, Coenraad Jacob Temminck introduced the form Hyrax sylvestris on the basis of a young individual from the land of the Ashanti in present-day Ghana (Temminck himself saw his animal as fully grown). His description is much more extensive than that of Fraser, which was obviously unknown to him. He compared the shape with the steppe forest tree hyrax from South Africa. Wilhelm Peters established Hyrax nigricans in 1879 , for which a female cub was available to him. The animal was found north of the mouth of the Congo near Chinchoxo. Three other forms go back to Oldfield Thomas . In 1887 he named Dendrohyrax emini , a very light variant based on a young animal, which was collected by Emin Pasha near Tingasi on the Uelle in the northern Congo basin. Thomas gave the name in honor of the finder. He also brought Procavia emini latrator close to them almost a quarter of a century later. This shape also appears relatively light. The specimen copy shows a full-grown female from Sankuru , a tributary of the Congo. Thomas Procavia presented marmota from Uganda as early as the turn of the century, emphasizing the particularly small build despite the juvenile character of the type shape. All of these forms were combined in 1934 by Herbert Hahn under the species Dendrohyrax dorsalis .

Threat and protection

The IUCN assesses the rainforest tree hybrids as "not endangered" ( least concern ) due to its large distribution area and the size of the population . A decline in the population of the species is not expected. No major threats are known, but the animals are sometimes sensitive to the fragmentation of habitats caused by deforestation. They are also hunted as a food resource and for their fur. On the island of Bioko , a significant increase in the number of carcasses of the species was registered in local bush meat markets in the 1990s . While 11 individuals were offered on the market in Malabo in 1991, the number increased to 23 in 1996. Due to hunting, the population density is very low near human settlements, but it increases in undisturbed regions. The species occurs in various nature reserves, including in the Taï National Park in the Ivory Coast or in the Upper Niger National Park in Guinea.

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)
  • Clyde Jones: Dendrohyrax dorsalis. Mammalian Species 113, 1978, pp. 1-4
  • Susanne Shultz and Diana Roberts: Dendrohyrax dorsalis Western 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. 155–157

Individual evidence

  1. ↑ a b c d e f g h i Clyde Jones: Dendrohyrax dorsalis. Mammalian Species 113, 1978, pp. 1-4
  2. ↑ a b c d e f g h i j k l m n 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)
  3. ↑ a b c d e f g h i j k l Susanne Shultz and Diana Roberts: Dendrohyrax dorsalis Western 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. 155–157
  4. ↑ a b c d Herbert Hahn: The family of the Procaviidae. Zeitschrift für Mammaliankunde 9, 1934, pp. 207–358 ( [1] )
  5. ^ Stefan Ziegler, Gerhard Nikolaus and Rainer Hutterer: High mammalian diversity in the newly established National Park of Upper Niger, Republic of Guinea. Oryx 36 (1), 2002, pp. 73-80
  6. ↑ a b c Simon K. Bearder, John F. Oates, Françoise Dowsett-Lemaire and Robert Dowsett: Evidence of an undescribed form of tree hyrax in the forests of western Nigeria and the Dahomey Gap. Afrotherian Conservation 11, 2015, pp. 2–5
  7. ^ A b T. Butynski, F. Dowsett-Lemaire and H. Hoeck: Dendrohyrax dorsalis. The IUCN Red List of Threatened Species 2015. e.T6410A21282601 ( [2] ); last accessed on December 2, 2017
  8. ^ B. Rio and G. Galat: Locomotion arboricole d'un Dendrohyrax dorsalis (Temminck, 1853). Mammalia 46 (4), 1982, pp. 449-456
  9. ↑ a b Bruno A. Djossa, Priscilla Zachée and Brice A. Sinsin: Activity patterns and habitat use of the Western Tree hyrax (Dendrohyrax dorsalis) within forest patches and implications for conservation. Ecotropica 18, 2012, pp. 65-72
  10. ↑ a b U. Rahm: Les mammifères de la forêt equatoriale de l'Est du Congo. Annales du Musée Royale de l'Afrique Centrale, Tervuren 149, 1966, pp. 37-121
  11. ^ A b Robert T. Hatt: The hyraxes collected by the American Museum Congo expedition. Bulletin of the American Museum of Natural History 72, 1936, pp. 117-139
  12. ^ U. Rahm: Notes sur le cri du Dendrohyrax dorsalis (Hyracoidea). Mammalia 33, 1969, pp. 68-79
  13. ^ A b Jean Roche: Nouvelles donnees sur la reproduction des hyracoides. Mammalia 26, 1962, pp. 517-529
  14. ^ Henri H. Mollaret: Naissance de damans en captive. Mammalia 25, 1962, pp. 529-532
  15. ↑ Bernd Hoppe-Dominik: Etude du specter des proies de la panthère, Panthera pardus, dans le Parc National de Taï en Côte d'Ivoire. Mammalia 48 (4), 1984, pp. 477-487
  16. ↑ Susanne Shultz: Population density, breeding chronology and diet of Crowned Eagles Stephanoaetus coronatus in Taï National Park, Ivory Coast. Ibis 144, 2002, pp. 135-138
  17. ↑ Satoshi Hirata, Gen Yamakoshi, Shiho Fujita, Gaku Ohashi and Tetsuro Matsuzawa: Capturing and Toying with Hyraxes (Dendrohyrax dorsalis) by Wild Chimpanzees (Pan troglodytes) at Bossou, Guinea. American Journal of Primatology 53, 2001, pp. 93-97
  18. ↑ A. Fain and FS Lukoschus: A new Psoroptidae (Acari: Astigmata) from Dendrohyrax dorsalis in Zaire. International Journal of Acarology 7 (1-4), 1981, pp. 143-146
  19. ↑ 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
  20. ^ 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
  21. ↑ Don E. Wilson and DeeAnn M. Reeder: Mammal Species of the World. A taxonomic and geographic Reference. Johns Hopkins University Press, 2005 ( [3] )
  22. ↑ Herbert Hahn: From tree, bush and clip sleepers. Wittenberg, 1959, pp. 1-88
  23. ^ Louis Fraser: Description of a new species of Hyrax from Fernando Po. Proceedings of the Zoological Society of London 20, 1852, p. 99 ( [4] )
  24. ^ John Edward Gray: Revision of the species of Hyrax, founded on the specimens in the British Museum. Annals and Magazine of Natural History 4 (1), 1868, pp. 35–52 ( [5] )
  25. ^ FA Jentink: On a new species of Hyrax (Hyrax stampflii) from Liberia. Notes from the Leyden Museum 8, 1886, pp. 209–212 ( [6] )
  26. ^ Coenraad Jacob Temminck: Esquisses zoologiques sur la Côte de Guine. 1st batch, les Mammifères. Leiden, 1853, pp. 1–253 (p. 182) ( [7] )
  27. ↑ Wilhelm Peters: About a new species of the mammalian genus Hyrax (H. nigricans) from Chinchoxo and about a new lizard, Platysaurus torquatus, from Mozambique. Meeting reports of the Society of Friends of Natural Science in Berlin 1879, pp. 10–11 ( [8] )
  28. ↑ Oldfield Thomas: On a collection of mammals obtaines by Emin Pasha in Equatorial Africa and presented by him to the Natural History Museum. Proceedings of the Scientific Meetings of the Zoological Society of London 1887, pp. 3–17 ( [9] )
  29. ↑ Oldfield Thomas: Diagnosis of two new Central African Mammalia. Annals and Magazine of Natural History 5 (20), 1887, p. 440 ( [10] )
  30. ↑ Oldfield Thomas: Further new African Mammalia. Annals and Magazine of Natural History 8 (5), 1910, pp. 282–285 ( [11] )
  31. ↑ Oldfield Thomas: On the more notable mammals obtained by Sir Harry Johnston in the Uganda Protectorate. Proceedings of the Zoological Society of London 1901, pp. 85-90 ( [12] )
  32. ↑ John E. Fa, Juan E. Garcia Yuste, and Ramon Castelo: Bushmeat Markets on Bioko Island as a Measure of Hunting Pressure. Conservation Biology 14 (6), 2000, pp. 1602-1613

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