Hyraxes or Dassies

Discussions and information on all Southern African Mammals
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Toko
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Hyraxes or Dassies

Post by Toko »

Hyraxes or Dassies are small, thickset, herbivorous mammals in the order Hyracoidea.

Scientific Classification

Phylum: Chordata
Class: Mammalia
Infraclass: Eutheria
SuperCohort: Afrotheria
Cohort: Paenungulata
Order: Hyracoidea (Dassies)
Family: Procaviidae

Dendrohyrax arboreus Southern Tree Hyrax

Heterohyrax brucei Yellow-spotted Hyrax, Bush Hyrax
Two subspecies may be found in Southern Africa:
Heterohyrax brucei granti Grant's Dassie
Heterohyrax brucei ruddi Limpopo Dassie

Procavia capensis Rock Hyrax
Two subspecies may be found in Southern Africa:
Procavia capensis capensis
Procavia capensis welwitschii Koakoveld Rock Hyrax

Dassies are considered to be the closest living relative of the largest land mammal, the African elephant, and also of the manatee and dugong. Afrotheria is recognized as one of the four major groups within the Eutheria (containing placental mammals). Paenungulata is a taxon that groups three extant mammal orders: Proboscidea (including elephants), Sirenia (sea cows, including dugongs and manatees), and Hyracoidea (hyraxes). The most convincing evidence for these relationships is based on DNA. There is currently only one species of Procavia recognised, but two other hyrax species, the yellow-spotted hyrax, Heterohyrax brucei and the southern tree hyrax, Dendrohyrax arboreus also occur in South Africa. However, these two species have much more restricted distributions. There is only one other species of Hyracoidea, the western tree hyrax, Dendrohyrax dorsalis, which occurs in Western and Central Africa.
Hyraxes share several unusual characteristics with elephants and sirenia (manatees and dugongs), which have resulted in them all being placed in the taxon Paenungulata. Male hyraxes lack a scrotum and their testicles remain tucked up in their abdominal cavity next to the kidneys, the same as elephants, manatees, and dugongs. Female hyraxes have a pair of teats near their arm pits (axilla), as well as four teats in their groin (inguinal area); elephants have a pair of teats near their axillae, and dugongs and manatees have a pair of teats, one located close to each of the front flippers. The tusks of hyraxes develop from the incisor teeth as do the tusks of elephants; most mammalian tusks develop from the canines. Hyraxes, like elephants, have flattened nails on the tips of their digits, rather than curved, elongated claws which are usually seen on mammals.


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Toko
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Re: Dassie - Animal of the Month May 2015

Post by Toko »

Characteristics: Dassies
Hyraxes retain a number of primitive mammalian characteristics; in particular, they have poorly developed internal temperature regulation, which they compensate for by behavioural thermoregulation, such as huddling together and basking in the sun. Unlike most other browsing and grazing animals, they do not use the incisors at the front of the jaw for slicing off leaves and grass, rather, they use the molar teeth at the side of the jaw. The incisors are nonetheless large, and grow continuously through life, similar to rodents. There is a small diastema between the incisors and the cheek teeth.

Although not ruminants, hyraxes have complex, multi-chambered stomachs that allow symbiotic bacteria to break down tough plant materials; their overall ability to digest fibre is similar to that of the ungulates. Although their mandibular motions are deceptively similar to chewing cud, the hyrax is physically incapable of regurgitation as in the even-toed ungulates and some of the macropods.

Hyraxes inhabit rocky terrain across sub-Saharan Africa and the Middle East. Their feet have rubbery pads with numerous sweat glands, which help the animal maintain its grip when quickly moving up steep, rocky surfaces. Hyraxes have peculiar, 3-toed hind feet with almost hoof-like nails on two of the toes (the inner toe has a claw). The forefeet have 5 toes. The soles of their fore- and hindfeet, which are moistened by special sweat glands, are remarkably soft and elastic, which works to increase their friction against the substrate. They have specialized muscles in the soles of the feet that help them to work almost like a suction cup. The feet of hyraxes are mesaxonic, meaning that the plane of symmetry of the foot goes through the third digit. In this they resemble perissodactyls.
They also have efficient kidneys, retaining water so that they can better survive in arid environments.

The skulls of hyraxes have a short rostrum, prominent postorbital processes that form a postorbital bar, small bullae, a large jugal that contributes to the glenoid fossa, and a broad plate-like angular region of the mandible. Hyraxes have a single incisor on each side of the upper jaw (two on the lower), followed by a diastema - an arrangement that looks very rodent-like. Like those of rodents, the incisors of hyraxes grow continuously and have enamel only on the anterior surface, creating a self-sharpening, chisel-like cutting edge.
The molars have strongly developed lophs, as is common in species with herbivorous diets. The dental formula is 1 / 2, 0 / 0, 4 / 4, 3 / 3 = 34.

Female hyraxes give birth to up to four young after a gestation period of between seven and eight months, depending on the species. The young are weaned at one to five months of age, and reach sexual maturity at 16 to 17 months.

Hyraxes live in small family groups, dominated by a single male who aggressively defends the territory from rivals. Where there is abundant living space, the male may dominate multiple groups of females, each with their own range. The remaining males live solitary lives, often on the periphery of areas controlled by larger males, and mate only with younger females.

Hyraxes have highly charged myoglobin, which has been inferred to reflect an aquatic ancestry.

The diet of hyraxes consists mostly of leaves, bark and grasses, but they also eat some insects. Some species are arboreal, while others live on rock outcrops. All are quick and agile climbers. They are active during daylight hours. Rock-dwelling species live in colonies; arboreal species tend to be solitary. All make a variety of whistles, chatters, and other sounds.

There is a single family of hyraxes, Procaviidae, and seven living species. Hyraxes are found in sub-Saharan Africa and Middle East.


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Toko
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Re: Dassie - Animal of the Month May 2015

Post by Toko »

How to distinguish Dassies in South Africa

Well, the three dasssie species of South Africa look more or less alike =O: 0: and there are lots of colour variations amongst populations. :O^

So best you start with looking at the range ;-)

Distribution

Southern Tree Hyrax

Image

In South Africa, it is only patchily distributed, it occurs in Afromontane forests and thickets of the Eastern Cape and KwaZulu-Natal provinces (Mist-belt forest through the KwaZulu-Natal Midlands; Woody Cape Section of Addo Elephant National Park).
In central Mozambique it occurs in lowland evergreen forests and in the evergreen riverine forests of the Save River.


Yellow-spotted Hyrax

Image

In the Southern African subregion they occur throughout Zimbabwe, except in the western and south-eastern parts; in Mozambique south of the Zambesi River in the western parts of Manica province and as far east as Gorogosa mountains in Sofala province; in the esatern part of Botswana; in Limpopo province of South Africa (Mapungubwe National Park).


Rock Hyrax

Image

In the Southern African subregion they occur in the inland escarpment and adjacent rocky areas in Namibia, north to the Angolan border, southern Zimbabwe, eastern Botswana, parts of north-western Mozambique, and narrowly in the west of Mozambique south of the Zambesi River; almost throuout South Africa; parts of Swaziland (not in the Lembobo Mountains) and Lesotho.


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Toko
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Re: Dassie - Animal of the Month May 2015

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Major Differences amongst the three Genera of Dassies

Image
(Mammals of Africa, Jonathan Kingdon, David Happold, Thomas Butynski, Michael Hoffmann, Meredith Happold, Jan Kalina)

Image

Image

Image


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Toko
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Re: Dassie - Animal of the Month May 2015

Post by Toko »

Rock Dassie Procavia capensis

The Dassie is small and stoutly built with short legs and a short rudimentary stump for a tail. In spite of its small rounded ears it has the appearance of a rabbit. A patch of black hair overlies a glandular area in the middle of the back. The feet are short and have rubbery pads with many sweat glands underneath. The sweat glands are important both for heat loss and provide the soles of the feet with remarkable traction on the rock surfaces.

The coat is coarse with long, black tactile hairs scattered amongst the shorter hair. Overall body colour varies according to habitat: grizzled greyish brown in moister areas, buff in arid regions. It looks darker when the coat is fluffed up in the cold, exposing the dark underfur, and glossy when the coat is sleeked down in hot conditions. Behind the ears is a buffy patch. The underparts are paler. The dorsum is usually darker than the flanks, and the venter tends to be a paler cream-color. The dorsal spot is usually black (dorsal spot cream, yellowish or reddish in yellow-spot rock dassie, white or off-white in tree hyrax). The dorsal crest is blackish in Procavia capensis capensis, and whitish cream in Procavia capensis welwitchii.

Body Length 45 - 60 cm; weight range 2.5 - 4.6 kg. Males are larger than females, and the tips of their incisor teeth show below the upper lip.

Dassies crop vegetation with the sides of their mouths, using their molars instead of the incisors as most mammals do. Their dentition is unusual. The 2 upper incisors resemble a short tusk-like canine. The shape of this canine in cross-section is sexually dimorphic, males have a triangular cross-section and females are more rounded in shape. There are 4 lower incisors.

Rock Dassies in Augrabies: Image


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Re: Dassie - Animal of the Month May 2015

Post by Richprins »

Fascinating!

I have one single dassie pic! \O


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Toko
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Re: Dassie - Animal of the Month May 2015

Post by Toko »

Let's see it lol


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Re: Dassie - Animal of the Month May 2015

Post by Richprins »

Will have to look! O-/

Didn't know there were 3 in SA!? ^Q^


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Re: Dassie - Animal of the Month May 2015

Post by Toko »

Ja, there is more biodiversity than most tourist know.

I have seen only two them because the Tree dassie is very elusive, rare and nocturnal. Have been looking and searching for years in the Natal Midlands :O^ :O^


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Re: Dassie - Animal of the Month May 2015

Post by Alf »

And a picture of yourself won't work RP :X:


Next trip to the bush??

Let me think......................
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