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The rock hyrax (''Procavia capensis'') or rock badger, also called the Cape hyrax and commonly referred to in South African English as the dassie, is one of the four living species of the order Hyracoidea, and the only living species in the genus ''Procavia''. Like all hyraxes, it is a medium-sized (~4 kg) terrestrial mammal, superficially resembling a guinea pig with short ears and tail. The closest living relatives to hyraxes are the modern-day elephants and sirenians. The rock hyrax is found across Africa and the Middle East, in habitats with rock crevices in which to escape from predators. It is the only extant terrestrial afrotherian in the Middle East. Hyraxes typically live in groups of 10–80 animals, and forage as a group. They have been reported to use sentries: one or more animals take up position on a vantage point and issue alarm calls on the approach of predators. The rock hyrax has incomplete thermoregulation and is most active in the morning and evening, although their activity pattern varies substantially with season and climate. Over most of its range, the rock hyrax is not endangered, and in some areas is considered a minor pest. In Ethiopia, Israel and Jordan, they have been shown to be a reservoir of the leishmaniasis parasite. ==Characteristics== The rock hyrax is squat and heavily built, adults reaching a length of and weighing around , with a slight sexual dimorphism, males being approximately 10% heavier than females. Their fur is thick and grey-brown, although this varies strongly between different environments: from dark brown in wetter habitats, to light gray in desert living individuals. Hyrax size (as measured by skull length and humerus diameter) is correlated to precipitation, probably because of the effect on preferred hyrax forage. Prominent in and apparently unique to hyraxes is the dorsal gland, which excretes an odour used for social communication and territorial marking. The gland is most clearly visible in dominant males.〔 The head of the rock hyrax is pointed, having a short neck with rounded ears. They have long black whiskers on their muzzles.〔http://www.livingdesert.org/animals/rock_hyrax.asp〕 The rock hyrax has a prominent pair of long, pointed tusk-like upper incisors which are reminiscent of the elephant, to which the hyrax is distantly related. The forefeet are plantigrade, and the hind feet semi-digitigrade. The soles of the feet have large, soft pads that are kept moist with sweat-like secretions. In males, the testes are permanently abdominal, another anatomical feature that hyraxes share with their relatives elephants and sirenians. Thermoregulation in the rock hyrax has been subject to much research, as their body temperature varies with a diurnal rhythm. However, animals kept in constant environmental conditions also display such variation〔 and this internal mechanism may be related to water balance regulation.〔Meltzer, A. (1973) ''Heat balance and water economy of the rock hyrax (Procavia capensis syriaca Schreber 1784).'' Unpubl. Ph.D. dissert., Tel-Aviv Univ., Israel, 135 pp.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Rock hyrax」の詳細全文を読む スポンサード リンク
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