Hyrax,
Hyrax
Common names: rock rabbit or dassie
HYRAXES OR DASSIES
Order Hyracoidea
Family Procaviidae
Rock hyrax or dassie, Procavia capensis
Bush hyrax or yellow-spotted rock dassie, Heterohyrax brucei
Tree hyrax or dassie, Dendrohyrax arboreus
Genus Dendrohyrax (tree hyraxes)
Species Dendrohyrax arboreus (southern tree hyrax)
Species Dendrohyrax dorsalis (western tree hyrax)
Species Dendrohyrax validus (eastern tree hyrax)
Genus Heterohyrax (hoggar hyrax and yellow-spotted hyrax)
Species Heterohyrax antineae (hoggar hyrax)
Species Heterohyrax brucei (yellow-spotted hyrax)
Genus Procavia (rock hyrax)
Species Procavia capensis (rock hyrax)
Species Procavia habessinica (Abyssinian hyrax)
Species Procavia johnstoni (Johnston's hyrax)
Species Procavia ruficeps (Sudan hyrax)
Eleven different species have been identified by specialists. But differences between species appear so minor to nonspecialists that only l species from each genus is included here-the 3 genera clearly are different.
WHAT THEY ARE
Survivors of an ancient group of near-ungulates (Paenungulata) that lumps together such strange bedfellows as elephants, aardvark, and dugongs. Once dominant herbivores that included animals the size of forest hogs, the only hyracoids that survived the ascension of true ungulates were small forms able to subsist in uncontested niches-namely kopjes, cliffs, and trees. To turn mammals with hooves instead of claws into agile rock and tree climbers is no mean feat. It shows how natural selection can retool a structure evolved for one function into a form serving a totally different purpose.
Small, tailless creatures with long bodies and short legs that look more like rodents (woodchucks/marmots) than ungulates. Minimal gender differences (testes internal, a link with elephants): adult males have thicker necks, blunter snouts. and sharper, stronger tusks; also a bigger larynx and air pouches that amplify territorial calls, Teeth.; Total 38; 2 upper incisors modifled as tusks (as in elephants), 4 lower incisors modified as a comb used in grooming. cheek teeth wasplike with transverse ridges (another link with elephants) for grinding vegetation. Feet: 4. front and 3 rear toes tipped with rounded nails (like an elephant's) except for a scratching/grooming claw on the inside back toe; bare, moist, rubbery soles (providing traction for climbing). Coat: soft fur in tree and bush hyraxes, harsh in rock hyrax, sprinkled with long sensory hairs. Color: shades of gray and brown with or without white underparts. Scent glands: a large dorsal gland located in a bare spot 1 to 3 in (25-75 mm) long and surrounded by an oval of lighter-colored, erectile hair, conspicuous when fanned open, secretion an aromatic fluid. Teats: 2 in armpits (elephantlike; lacking in some tree hyraxes), 2 or 4 on belly.
SOCIAL/MATING SYSTEM
Adult males of all species are territorial. Bush and rock hyraxes live in colonies typically composed of a male with a harem of several related females and their offspring. Often sharing the same rocks and even the same sleeping and sunning spots, these two species associate more closely than any other African mammals, except for some forest monkeys.
Tree hraxes are solitary or live in families composed of a mated pair and their offspring. However, this hyrax also lives in colonies very similar to the other two high on certain mountains (see account).
Although hyraxes huddle together for warmth, social relations are often aggressive, and they do not engage in social grooming like other contact species.
HOW THEY MOVE
In a creeping walk-especially on cold mornings before sunbathing. They can jump-gallop 11 mph (18 kph) for up to 130 yards, are good jumpers and great climbers-the only ungulates that can scale smooth trees and rocks. Too long and low to sit up or walk bipedally, they crouch on all fours with back bowed, lie prone with forelegs extended and head resting between them, and extend hind legs with soles up to dissipate excess body heat.
HOW THEY COMMUNICATE
Sight, scent, sound.
HYRAX BEHAVIOR QUIDE
Expect to see and hear >' Usual context and meaning
Territorial Advertising
Adult male on lookout point in distinctive posture, calling with head raised and jaws parted, and dorsal gland fanned open. Advertising calls of the 3 species are totally different (see species accounts). Calling bouts may continue for up to 5 min. and be repeated at intervals all night- Neighbors are often stimulated to reply.
White stains on vertical rock surfaces, created by hyrax urine. > Rock and bush hyraxes both urinate at these sites, which advertise an active colony. Crystallized calcium carbonate makes the stain.
Aggression
Approach/stare.
Opening dorsal gland and brisking neck hair; secretion can be seen and smelled.
Raising head and shoulders.
Showing tusks by retracting upper lip.
Grinding molars, growling, showing white membrane over eyes.
Snapping, biting.
Chasing.
Confrontations, Face-to-face meetings provoke low-level threats (erecting dorsal gland fringe, showing tusks). Nonbelligerents avoid face-to-face meetings.
Presenting rump, backing up. Defensive posture.
Position during fights. Combatants back into each other, maneuver for opportunity to stub; open glands wide, exuding scent. Tusks can inflict fatal wounds.
Submission/surrender
Closing dorsal gland, flattening ears, running from aggressor.
Sociable Behavior
Sunbathing. Juveniles perch on adults.
Orientation while huddling and sunbathing. Positioned to avoid confrontations.
Depositing droppings (rabbit-sized pellets) in communal latrine.
Mother and Offspring
Nursing offspring switch between fore and aft nipples. Nursing attempts are often preceded by intense twittering.
Mothers whinnying while suckling, with tusks exposed.
Newborns uttering a 2 syllable twitter of distress; mothers respond with a lower, more gutteral twitter while coming to their aid.
Play
Chasing and fighting games. Commonest during morning sunning sessions.
Response to Predators
Rapid flight and leaping across raps; taking refuge in holes.
Playing dead, after being caught by predator. Hyraxes sometimes escape when predator dallies before feeding.
Reprinted from "The Safari Companion" by Richard Estes
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