In early Neocene, after extinction of significant part of species of ungulates, representatives of earlier not numerous and uniform group of hyraxes had got an opportunity to show their evolutionary potential. Among them representatives of separate phylogenetic line of running hyraxes had appeared – subfamiliy Dromohyracinae in Hyracidae family. These animals gradually passed from burrowing habit of life to existence in plain district. After great split of Africa the part of species of this group had remained on continent and evolved to giant species. And the species isolated at the East-African subcontinent, had changed much less. At Zinj Land representatives of this basal group of hyraxes had remained.
In forests growing on plains and in foothills one of such species of running hyraxes lives. Its distinctive feature is a presence of pair of short horn-like outgrowths on head; because of this feature the animal has received the name forest horned cony. This is a pig-sized ground mammal: it weighs about 50 kg at body length up to 70 cm. Legs of animal are longer, rather than at common hyraxes of Holocene epoch, and forest horned cony is able to run quickly. Hand and foot are digitigrade. Despite of massive constitution, animal dexterously jumps over high plank-buttress roots of tropical trees, escaping from chasing of predators, and is able to change direction of run sharply. By habit of life it resembles caviomorph rodents of South America like agouti or paca very much. This animal lacks tail appreciable from outside. Bones of upper part of skull of forest horned cony are thickened and form a kind of helmet. On nose bridge of animal two conic horns directed upwards and forward grow; these structures are covered with dense cornificated hairless skin. Both males and females have them, and their application is various: at males horns serve for courtship tournaments and establishment of domination out of breeding season, and representatives of both genders also use horns for digging holes and protection against enemies. The attacked horned cony, not having an opportunity to escape in flight, attacks on predator, and strikes impacts by head, ramming the aggressor. Small eyes are slightly shifted downwards and protected by edges of bone “helmet”. Colouring of wool is dark brown with white spots on sides of head and on stomach. Male and female do not differ in colouring. The cub does not have white spots. Forest horned cony lives in family groups consisting of large male, several females of various ages and their cubs. Shelter for family of animals is the hole about half meter wide and over ten meters long, directing under ground to almost three-meter depth. In hole there is well equipped inhabited chamber covered by vegetative material, some temporary toilet holes where animals leave dung and urine, masking their presence, and 2 – 3 carefully disguised emergency exits. These animals do not have seasonal prevalence in breeding, and in family group always there are cubs of various ages. Pregnancy lasts till about three months. The female gives rise to 3 – 4 well advanced cubs born with opened eyes. They become sexually mature at the age of about two years. At Zinj Land close species of horned conies live:
Mountain horned cony (Ceratohyrax crassipygus) lives in mountain areas of Zinj Land, preferring dry bushy districts and thickets of grasses. It is larger, rather than forest horned cony, because it lives in cooler climate with expressed daily and seasonal fluctuations of temperatures. At cold snap this species runs to not deep dormation. In warm season when food is plentiful, on buttocks of mountain horned cony thick layer of fat is accumulated; it is used in winter time. Colouring of wool at this animal is lighter, than at forest species – straw-coloured with grayish shade on back, hips and waist. Horns on skull are thicker and shorter, than at forest species. With their help animal can pick out from the ground stones during the hole digging. This species settles in pairs, but does not avoid presence of congeners.
Dwarf horned cony (Ceratohyrax minimus) inhabits high-mountainous meadows of Zinj Land. It is a marmot-sized species weighting no more than 6 kgs. It has short horn-looking outgrowths of skull, and rich wool has dark, almost black color without marks both at adult individuals, and at cubs. This animal is able to climb and jump on rocks, searching for grassy plants. In summer dwarf horned cony also accumulates fat which is depositing on buttocks and hips. In conditions of high mountains at downturn of temperature it runs into deep dormation which lasts not less than 3 months. At this time animal uses the saved up fat stocks.