The eastern tree hyrax (''Dendrohyrax validus'') is a species of mammal within the family

Procaviidae Hyraxes (), also called dassies, are small, thickset, herbivorous mammals in the order Hyracoidea. Hyraxes are well-furred, rotund animals with short tails. Typically, they measure between long and weigh between . They are superficially simi ...

. The eastern tree hyrax is the most localized of the

tree hyrax The tree hyrax or tree dassie is a small nocturnal mammal native to Africa. Distantly related to elephants and sea cows, it comprises the four species in the genus ''Dendrohyrax'', one of only three genera in the family Procaviidae, which is t ...

species, distributed patchily in a narrow band of lowland and

montane forests Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucial f ...

in Kenya and Tanzania and adjacent islands.

Description

The eastern tree hyrax is a small, rotund guinea pig-like mammal with dense, soft fur and blunt, nailed toes. They weigh on average 2.75 kg and have a head-body length of 470–558 mm. No tail is discernible. Pelage is variable, with dorsal coloration ranging from cinnamon brown to blackish, and a paler underside. Individuals also have a distinctive dorsal scent gland marked by a contrasting, light-colored patch of hairs. Considerable variation exists between subspecies as currently described. The rostrum is relatively long, but well-haired, unlike the related western tree hyrax. Individuals of this species are difficult to distinguish from the related southern tree hyrax, which was previously considered conspecific; however, the fur of southern tree hyrax is usually more grizzled.

Behavior

The eastern tree hyrax is solitary, living in tree holes, and communicates with other individuals via repetitive vocal calls and scent marking. Most roosts are occupied by only one animal, with the exception of females with one young. They are skilled climbers which feed predominantly in the

canopy Canopy may refer to: Plants * Canopy (biology), aboveground portion of plant community or crop (including forests) * Canopy (grape), aboveground portion of grapes Religion and ceremonies * Baldachin or canopy of state, typically placed over an a ...

on tree leaves, and form large

midden A midden (also kitchen midden or shell heap) is an old dump for domestic waste which may consist of animal bone, human excrement, botanical material, mollusc shells, potsherds, lithics (especially debitage), and other artifacts and ecofact ...

s adjacent to roost trees.

Ecology

Eastern tree hyraxes are largely restricted to montane forests, but also occur in adjacent lowland forests and even tropical dry forests on coral in Zanzibar and Pemba. They are most abundant at lower elevations, but occur as high as 3,070 meters on Mt. Kilimanjaro, albeit in reduced densities due to the scarcity of large trees. In 2015, the IUCN designated the eastern tree hyrax as Near Threatened (NT). Its main threats include deforestation and hunting, and individuals often fall prey to dogs. Known natural predators include

leopard The leopard (''Panthera pardus'') is one of the five extant species in the genus '' Panthera'', a member of the cat family, Felidae. It occurs in a wide range in sub-Saharan Africa, in some parts of Western and Central Asia, Southern Russia, a ...

crowned eagle The crowned eagle, also known as the African crowned eagle or the crowned hawk-eagle (''Stephanoaetus coronatus''), is a large bird of prey found in sub-Saharan Africa; in Southern Africa it is restricted to eastern areas.Sinclair & Ryan (2003) ...

, and African python.

Distribution

The Eastern tree hyrax is endemic to the

East Africa East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territories make up Eastern Africa: Due to the historical ...

n countries of Tanzania and Kenya; they predominantly inhabit the foothills and montane forests of

Mount Kilimanjaro Mount Kilimanjaro () is a dormant volcano in Tanzania. It has three volcanic cones: Kibo, Mawenzi, and Shira. It is the highest mountain in Africa and the highest free-standing mountain above sea level in the world: above sea level and ab ...

Mount Meru Mount Meru (Sanskrit/Pali: मेरु), also known as Sumeru, Sineru or Mahāmeru, is the sacred five-peaked mountain of Hindu, Jain, and Buddhist cosmology and is considered to be the centre of all the physical, metaphysical and spiritu ...

and the

Eastern Arc Mountains The Eastern Arc Mountains is a chain of mountains found in Kenya and Tanzania. The chain runs from northeast to southwest, with the Taita Hills being in Kenya and the other ranges being in Tanzania. They are delimited on the southwest by the fau ...

. The Eastern Arcs feature an ancient chain of isolated, relict forests, stretching from the

Taita Hills The Taita Hills, sometimes also spelled as Teita Hills, are a mountain range located in the Taita-Taveta County in south-eastern Kenya. The hills consist of three massifs: Dawida, Sagalla in the southern side of Voi township and Kasigau in ...

of Southern Kenya to the

Udzungwa Mountains The Udzungwa Mountains are a mountain range in south-central Tanzania. The mountains are mostly within Iringa Region, south of Tanzania's capital Dodoma. The Udzungwa Mountains are part of the Eastern Arc Mountains, and are home to a biodiverse ...

of Tanzania. Hyraxes are also present on the coast between

Tanga Region Tanga Region (''Mkoa wa Tanga'' in Swahili) is one of Tanzania's 31 administrative regions. The region covers an area of . The region is comparable in size to the combined land area of the nation state of Burundi. The regional capital is the mun ...

, Tanzania, and

Mombasa Mombasa ( ; ) is a coastal city in southeastern Kenya along the Indian Ocean. It was the first capital of the British East Africa, before Nairobi was elevated to capital city status. It now serves as the capital of Mombasa County. The town is ...

, Kenya, as well as on the islands of

Zanzibar Zanzibar (; ; ) is an insular semi-autonomous province which united with Tanganyika in 1964 to form the United Republic of Tanzania. It is an archipelago in the Indian Ocean, off the coast of the mainland, and consists of many small islands ...

and

Pemba Pemba may refer to: __NOTOC__ Places * Pemba Island, in Tanzania * Pemba, Mozambique, the capital of Cabo Delgado Province * Pemba, Zambia, a small town Individuals * George Pemba, South African painter * Pemba (panda), a red panda * Tsewang Yishe ...

Taxonomy

The eastern tree hyrax is currently considered to have four subspecies: *''D. v. validus'', found on Mt. Kilimanjaro and Mt. Meru, *''D. v. terricola'', found in the Usambara and Pare Mountains, **Eastern tree hyraxes in Taita Hills were recently recorded and, based on call structure, likely represent individuals of this subspecies.Rosti H, Pihlström H, Bearder S, Pellikka P, Rikkinen J. Vocalization Analyses of Nocturnal Arboreal Mammals of the Taita Hills, Kenya. ''Diversity''. 2020; 12(12):473. https://doi.org/10.3390/d12120473Rosti H, Heiskanen J, Loehr J. et al. Habitat preferences, estimated abundance and behavior of tree hyrax (Dendrohyrax sp.) in fragmented montane forests of Taita Hills, Kenya. ''Sci Rep''. 2022; 12:6331. https://doi.org/10.1038/s41598-022-10235-7 Taita tree hyrax

*''D. v. neumannii'', found on the islands of Zanzibar and Pemba, and *''D. v. schusteri'', found in the Uluguru and likely the Udzungwa and Rubeho mountains. The subspecific status of relict populations of Eastern Tree Hyrax described from coastal Southern Kenya is currently unclear.Hoeck HN, Seibt U, Wickler W. Dendrohyrax validus True, 1890 in Kenia. ''Mammalian Biology (früher Zeitschrift für Säugetierkunde)''. 1976; 42:115-118. These populations have been described as using rock crevices as habitat, contrasting with ''Dendrohyrax''’s usually-arboreal behavior. These subspecies display considerable vocal and morphological variation, thus, some researchers consider Eastern Tree Hyrax to represent a complex of 3-4 distinct species, with further revision required.Hoeck HN. Some thoughts on the distribution of Tree Hyraxes (Genus Dendrohyrax) in northern Tanzania. ''Afrotherian Conservation''. 2017; 13:47-49.

References