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Yellow-spotted rock hyrax

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Yellow-spotted rock hyrax[1]
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Mammalia
Order:
Hyracoidea
Family:
Procaviidae
Genus:
Heterohyrax

Gray, 1868
Species:
H. brucei
Binomial name
Heterohyrax brucei
(Gray, 1868)
Subspecies

25, see text

Yellow-spotted rock hyrax range
Family, Serengeti, Tanzania

The yellow-spotted rock hyrax or bush hyrax (Heterohyrax brucei) is a species of mammal in the family Procaviidae. It is found in Angola, Botswana, Burundi, Democratic Republic of the Congo, Southern Egypt, Eritrea, Ethiopia, Kenya, Malawi, Mozambique, Rwanda, Somalia, Northern South Africa, Sudan, Tanzania, Uganda, Zambia, and Zimbabwe. Unlike the rock hyrax, it is not found outside of Africa.[3] Its natural habitats are dry savanna and rocky areas.[2]

It is currently the only species in the genus Heterohyrax. However, there are 25 distinct subspecies.[1]

It feeds on small grasses, herbage, leaves, fruit, insects, lizards, and birds' eggs.[4]

Naming and Classification

The heterohyrax is a bush hyrax, as opposed to a rock hyrax (Procavia capensis).[5] The two are distinguishable as the bush hyrax is less heavily built in comparison to the rock hyrax. The bush hyrax also has a narrower muzzle than the rock hyrax.[6] Common names include: yellow-spotted hyrax, bush hyrax, hogger hyrax, yellow-spotted rock hyrax, and daman de steppe (French).[2]

The genus heterohyrax contains one extinct species, H. auricampensis, and one living, H. brucei. Within H. brucei there are 25 recognized subspecies.[6]

The heterohyrax belong to the superordinal clade of endemic African mammals that includes elephant shrews, aardvarks, golden moles, elephants and sirenians.[7]

Subspecies

(alphabetically arranged)[1]

  • H. b. albipes
  • H. b. antineae
  • H. b. bakeri
  • H. b. bocagei
  • H. b. brucei (type species)
  • H. b. chapini
  • H. b. dieseneri
  • H. b. frommi
  • H. b. granti
  • H. b. hindei
  • H. b. hoogstraali
  • H. b. kempi
  • H. b. lademanni
  • H. b. manningi
  • H. b. mossambicus
  • H. b. muenzneri
  • H. b. princeps
  • H. b. prittwitzi
  • H. b. pumilus
  • H. b. ruddi
  • H. b. rudolfi
  • H. b. somalicus
  • H. b. ssongeae
  • H. b. thomasi
  • H. b. victorianjansae

Conservation

The Heterohyrax is on the “least concern” list for threatened species.[8] It has no major threats, though it is locally hunted in some regions. Communities within the Matobo hills are reliant upon the hyraxes as a main protein source.[9] Other poplulations of people groups have been known to hunt the hyrax when other food sources are scarce.[10]

Population and Habitat

Populations of the bush hyrax are native to more than 25 African countries.[11] Extending from Sudan and Eritrea in northern Africa and east through the Horn of Africa. They also live as far south as the Limpopo Province in South Africa. Additionally, isolated populations are known to be in the south west of the Democratic Republic of Congo and Angolia.[12][13]

Their habitats are restricted to rocky kopjes, or rocky, elevated areas on a generally flat plain, sheer rock faces (krantzes) and piles of large boulders with openings of at least 11 cm in height with one square meter of floor space.[12][13] Rocky habitats are suitable because it is topographically complex containing a multitude of crevices and cavities in which animals can nest, seek shelter, and find shade.[14] They live in varying climates from dry savannas to dense rain forests and cold afro-alpine moorlands.[11] They can also live at varying elevations. In east Africa they are known to live at about 3800 m[15] but they are also found at elevations over 4200 m.[11]

The bush hyrax lives in populations ranging between 20 and 53 individuals[7][11] with one dominant male and several females and juveniles of both sexes. Other adult males tend to live on the periphery of the territory of dominant males.[7]

Studies have been conducted observing populations of bush hyraxes in the Matobo National Park, Zimbabwe. In this region populations have experienced considerable declines since 1978. Droughts in the Matobo National Park are considered as a causal factor in this decline.[16] However, in the Matobo National Park predation is high. This study showed a 52-76% mortality rate within the first year of life.[6]

The bush hyraxes, Heterohyrax brucei, are known to live with rock hyraxes,Provaia capensis.[6] However, different species of hyraxes do not interbreed because their sex organs vary significantly.[7] Some behaviors observed in populations of rock and bush hyraxes includes caring for each others young by sharing nurseries[6] as well as inhabiting the same rock crevices.[6] The associations observed between these hyraxes is variable and studies in Zimbabwe have shown that they often mix near parturition, or around the time of giving birth.[12]

Morphology

Name giving feature

The name giving feature of the yellow-spotted rock hyrax is a dorsal gland that is located beneath a raised skin patch about 1.5 cm long and is surrounded by erectile hairs.[12] The secretions of the gland stain a dorsal spot of reddish-ochre to a dirty white coloration, but most commonly appears yellow. The gland is associated with sexual arousal and also plays a role in maternal recognition by young.[6] The bush hyrax is also noted to have a white patch of hair above the eyes.[11]

General features

The bush hyrax ranges from an average of 2.4 kg to a maximum of 3.6 kg, while males tend to be slightly larger than females. They have short legs, a rudimentary tail and round ears. They have been described to appear and act rabbit- or guinea pig-like.[5][17] Their lateral and dorsal coloration tends to be grey among colonies found in arid regions and a dark reddish-brown among those found in more mesic regions.[12][6] Their pelts are thick and course ranging from 305–380 mm in length.[17] Additionally they have vibrissae that provide tactile feedback located above the eyes, under the chin, along the back and sides, on the abdomen and on the fore- and hind limbs. They measure 90 mm long on the snout, and 70 mm elsewhere.[6]

Since the bush hyrax is found in varying geographic locations they have been reported to maintain body temperatures as low as 24 C and as high as 37 C.[12]

The molars of the hyrax are brachydont and the upper incisors appear tusk-like.[6] They also have four lower incisors that are comb-like and used to groom the fur.[12]

Other noted features include: the Jacobsen’s organ which is as a specialized olfactory structure, a compartmentalized stomach into nonglandular cranial and glandular caudal sections, and a vertebral column that is convex from neck to tail.[6]

Specialized characteristics

They bush hyrax also has specialized glands on the pads of their feet that increase their grip which helps them navigate slick rock surfaces.[12][13] The pads of their feet are flat and naked while secretions from these glands keep the pads moist. The musculature of the feet contract the foot into a cup like shape, thus resulting in a suction cup-like effect.[17] Hyraxes are known to be excellent climbers due to this specialization (14) and it has even been observed that if shot, they will remain perpendicular on the rock surface as if stuck to the surface.[18] The forepaw has three well-developed digits, a rudimentary thumb, and a small fifth digit. Their digits have flat, hoof-like nails, except for the second digit, which has long, curved claws that are used for grooming.[12] The hind paw is similar except lacking a big toe and the fifth digit is rudimentary.

The bush hyraxes have an umbraculum in the pupil of their eye extending from the iris. This enables them to stare into the sun and watch for aerial predators while they sun bask.[6][12]

The bush hyrax has a specialized kidney to compensate for the lack of water available in their natural habitat. This enables them to conserve water by producing a highly concentrated urine. The urine is so concentrated that is leaves a crystalline residue called klipstreet or hyraceum that is commonly found on the rock outcroppings where they reside.[12][19]

Reproductive

The penis of the bush hyrax is complex and distinct from that of the other hyrax genera. It has a short, thin appendage within a cuplike glans penis and measures >6 cm when erect. Additionally, it has been observed that the bush hyrax also has a greater distance between the anus and preputial opening in comparison to other hyraxes. The testes are permanently intra-abdominal and vary in size depending upon season.[6]

Females have one pair of pectoral and two pairs of inguinal mammae. Uterus is bicornuate, placenta is chorioallantoic.[6]

Genetic variability

Genetic variation is minimal within the hyrax species. Genetic variation analysis suggests that females have a higher rate of gene transfer, this may be due to greater migration success and longer distance migration of females than males. Data also shows that females immigrate into colonies more frequently than males.[7]

Life Cycle

The bush hyrax has been recorded to live between 10 and 14 years in the wild.[16][17][20][21] Males and females reach sexually maturity as early as 16 months of age and as late as 28 months with no recorded differences between sexes.[22][23][17][24]

Sexually mature females breed annually and breeding seasons vary based on geographic location. Peak birth rates among colonies in Kenya occur between February and March, in Zimbabwe March, and in the Serengeti, Tanzania between December and January. Breeding seasons are 7-8 months prior to when these peak birth rates have been observed based on length of gestation.[6][25] Females of colonies living at high elevation enter in estrus as the photoperiod increases.[6] Their estrus cycle is 1-5 days. For example, in the Serengeti, there is a discrete mating season of seven weeks in which females with enter estrus several times for several days each.[26] Litters usually consist of 1-4 young, with an average of 1.9. Young are born in a fur-lined nest and on average weigh 225 grams.[13][17] They are born open-eyed, furred, and are able to follow adults out of the nest within several hours of birth. Young are suckled for 1-6 months before they are weaned.[27][28][6]

Juvenile mortality rate is high due to predation. Rock pythons, leopards, birds of prey, mongooses, and other small carnivores prey upon the bush hyrax.[29] One study conducted between 1992-95 estimated that juvenile mortality was 52.4%-61.3% per annum.[16]

Behavior

Feeding habits

The bush hyrax is a “browser” in regards to its eating habits.[16] They spend 80% of foraging time browsing on twigs and bark of woody tree species as well as on leaves, buds, flowers and fruits of trees, bushes and forbs. Only rarely will they consume grass.[12] Additionally, one study reported that a colony of bush hyraxes in Zambia feeds on the leaves of bitter yams. Another study in Kenya reported that while they do not routinely feed on grasses they rely on grasses during wet seasons.[17] Furthermore it has been reported that in the Serengeti National Park thy hyraxes feed in the morning and evening, eating more in the wet season in comparison to the dry season.[18] Group feeding is common and occurs up to 50 m from the colony’s shelter. However, lone feeding also occurs but only up to 20 m from their shelter.[6] Bush hyraxes have also been known to climb trees in order to obtain food.[18]

Since their habitat is dry with scarce water, they get all the water they need from the vegetation they consume.[6]

General behavior

While they are diurnal, 95 percent of the day is spent resting in the sun.[6] While sun basking is necessary for thermoregulation, it greatly increases their risk of predation. However, they remain vigilant[6] and the dominant male will keep watch on a high rock and will give a shrill alarm if there is danger.[18] Colonies of hyraxes include on average 34 individuals, but stable polygamous family groups make up the basic social unit. While they do spend much time sun basking, they are highly social animals. Play behavior includes fur nipping, biting, climbing, pushing, fighting, chasing, and mounting.[6]

If they are attacked or threatened, they will bite aggressively. Their keen eyesight and good hearing keeps enables them be aware of predators and possible threats.[13][18]

Other documented behaviors include dust bathing to rid themselves of parasites.[6] They also habitually defecate and urinate in designated locations where they reside.[11]

Parasitology

The bush hyrax is known to be a reservoir for Leishmania aethiopica. A study captured 48 hyraxes from various colonies from 3 different locations in Ethiopia. Of these, three were infected with Leishmania aethiopia. However, there were no visible legions and no amastogote stage parasites present, thus it was concluded that the bush hyrax is a reservoir and not a suitable host. The vector of Leishmania aethiopica is Phlebotomus longipes.[30]

References

Wikimedia Commons has media related to Heterohyrax brucei.
Wikispecies has information related to Heterohyrax.
  1. ^ a b c Shoshani, J. (2005). Wilson, D.E.; Reeder, D.M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 88. ISBN 978-0-8018-8221-0. OCLC 62265494.
  2. ^ a b c Template:IUCN2008
  3. ^ http://animaldiversity.ummz.umich.edu/site/accounts/information/Heterohyrax_brucei.html
  4. ^ Hyrax, Out of Africa
  5. ^ a b Barry, R. E., & Mundy, P. J. (2002) Seasonal variation in the degree of heterospecific association of two syntopic hyraxes (Heterohyrax brucei and Procavia capensis) exhibiting synchronous parturition. Behavioral Ecological and Sociobiology (52), 177-181.
  6. ^ a b c d e f g h i j k l m n o p q r s t u v w Barry, R.E., & Shoshani, J. (2000). Mammal Species: Heterohyrax brucei. American Society of Mammalogists. 645:1-7.
  7. ^ a b c d e Gerlach, G. & Hoeck, H.N. (2001). Islands on the plains: metapopulation dynamics and female biased dispersal in hyraxes (Hyracoidea) in the Serengeti National Park. Molecular Ecology. 10:2307-2317.
  8. ^ Barry, R., Bloomer, P., Hoeck, H. & Shoshani, H. (IUCN SSC Afrotheria Specialist Group) 2008. Heterohyrax brucei. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1. <www.iucnredlist.org>.
  9. ^ Ngoni, C. (2007). Black Eagles and hyraxes- the two flagship species in the conservation of wildlife in the Matobo Hills, Zimbabwe. Ostrich: The Journal of African Ornithology. (78;2) pp. 381-386.
  10. ^ Nowak, R. M. (1999). Gray Hyraxes or Yellow-spotted Hyraxes, In: Walker’s Mammals of the World. Vol. 1.JHU Press. Pp. 1044-1046.
  11. ^ a b c d e f African Wildlife Foundation. Hyrax. http://www.awf.org/wildlife-conservation/hyrax. Retrieved: 10/7/13
  12. ^ a b c d e f g h i j k l Kingdon, J., Happold, D., Butynski, T., Hoffmann, M., Happold, M., & Kalina, J. (2013). Mammals of Africa. A & C Black. pp. 161-165
  13. ^ a b c d e Shefferly, N. (1999). Heterohyrax brucei. Animal Diversity Web. http://animaldiversity.ummz.umich.edu/accounts/Heterohyrax_brucei/. Retrieved 10/8/13
  14. ^ Wolff, J. O., & Sherman, P. W. (2008). Rodent Societies: An Ecological and Evolutionary Perspective. University of Chicago Press. pp. 418
  15. ^ Barry, R., Bloomer, P., Hoeck, H. & Shoshani, H. (IUCN SSC Afrotheria Specialist Group) 2008. Heterohyrax brucei. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1. <www.iucnredlist.org>
  16. ^ a b c d Barry, R.E. & Mundy, P.J. (1998). Population dynamics of two species of hyraxes in the Matobo National Park, Zimbabwe. African Journal of Ecology. 36:221-233.
  17. ^ a b c d e f g Encyclopedia of Life. Heterohyrax brucei: Yellow-spotted Rock Hyrax. http://eol.org/pages/326383/details. Retrieved: 10/7/13
  18. ^ a b c d e Nowak, R. M. (1999). Gray Hyraxes or Yellow-spotted Hyraxes, In: Walker’s Mammals of the World. Vol. 1.JHU Press. pp. 1044-1046.
  19. ^ Vaughan, T. A., Ryan, J. M., & Czaplewski, N. J. (2011). Mammalogy. Jones & Bartlett Publishers. pp. 142-144.
  20. ^ Gerlach, G. & Hoeck, H. N. (2001). Islands on the plains: metapopulation dynamics and female biased dispersal in hyraxes (Hyracoidea) in the Serengeti National Park. Molecular Ecology. (10) 2307-2317.
  21. ^ Vaughan, T. A., Ryan, J. M., & Czaplewski, N. J. (2011). Mammalogy. Jones & Bartlett Publishers. pp. 142- 144
  22. ^ Nowak, R. M. (1999). Gray Hyraxes or Yellow-spotted Hyraxes, In: Walker’s Mammals of the World. Vol. 1.JHU Press. Pp. 1044-1046.
  23. ^ Hayssen, V. D., & Tienhoven, A. V. (1993). Asdell’s Patterns of Mammalian Reproduction: A compendium of Species-specific Data. Cornell University Press. Pp. 373-375
  24. ^ Gerlach, G. & Hoeck, H. N. (2001). Islands on the plains: metapopulation dynamics and female biased dispersal in hyraxes (Hyracoidea) in the Serengeti National Park. Molecular Ecology. (10) 2307-2317.
  25. ^ Hayssen, V. D., & Tienhoven, A. V. (1993). Asdell’s Patterns of Mammalian Reproduction: A compendium of Species-specific Data. Cornell University Press. Pp. 373-375
  26. ^ Nowak, R. M. (1999). Gray Hyraxes or Yellow-spotted Hyraxes, In: Walker’s Mammals of the World. Vol. 1.JHU Press. Pp. 1044-1046.
  27. ^ Nowak, R. M. (1999). Gray Hyraxes or Yellow-spotted Hyraxes, In: Walker’s Mammals of the World. Vol. 1.JHU Press. Pp. 1044-1046.
  28. ^ Hayssen, V. D., & Tienhoven, A. V. (1993). Asdell’s Patterns of Mammalian Reproduction: A compendium of Species-specific Data. Cornell University Press. Pp. 373-375
  29. ^ Nowak, R. M. (1999). Gray Hyraxes or Yellow-spotted Hyraxes, In: Walker’s Mammals of the World. Vol. 1.JHU Press. Pp. 1044-1046.
  30. ^ Lemma, W., Erenso, G., Gadisa, E., Balkew, M., Gebre-Michael, T. & Hailu, A. (2009). A zoonotic focus of cutaneous leishmaniasis in Addis Ababa, Ethiopia. Parasites and Vectors. (2) 60


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