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Okapi (Okapia johnstoni) Fact Sheet: Physical Characteristics

Okapi Okapia johnstoni

Physical Characteristics

Body measurements

AttributeMalesFemales
Weight 180-260 kg (397-573 lb) 240-356 kg (529 - 785 lb)
Shoulder height 1.40-1.55 m (4.6-5.1 ft) 1.42-1.59 m (4.7-5.2 ft)
Body length 2.5 m (8 ft) average for both sexes
Tail length 30-42 cm (12-17 in)

Data sources: Hart (2013)

General Appearance

General

  • Medium sized, extremely shy, even-toed ruminant related to giraffes
    • Adapted for dense forest living
    • Smaller than giraffes, with shorter necks (but necks still longer than most ruminants)
    • Okapi backs are nearly level, while giraffe backs slope markedly towards the rear.
  • Long skull, large black eyes, large ears
  • Teeth show giraffe-like pattern with large gap between incisors and premolars.
    • 32 teeth
    • Enamel is rough or wrinkled, like giraffes'
    • Canine teeth are lobed, as are those of giraffes; lobes most obvious in unworn teeth of calves.
  • Large bony capsule enclosing the middle ear bones (auditory bullae), common to many forest-dwelling ruminants (Colbert 1938)
    • These ear bones enhance hearing (plains-dwelling giraffes have much smaller auditory bullae).
    • Can hear and transmit low-frequency sounds below audible range for humans, according to studies in 1992 at the San Diego Zoo and White Oak Conservation Center, Florida. (Lindsey et al 1999)
  • Large sinuses in palate
  • Muzzle is narrow, nearly pointed, lips mobile and muscular; together with tongue these adaptations well suited to selective feeding on preferred plants.
  • Long, prehensile tongue (proportionally longer than the giraffe's).
    • Dark-bluish colored with pointed extremity, smooth base, and papillae on surface.
    • Can be extended 25 cm beyond snout to groom whole body, even wiping the eyes, cleaning the ears and nostrils.
  • Skin-covered horn-like ossicones
    • Permanent (not shed, like horns)
    • Giraffes also have ossicones
  • Poor eyesight
  • Cervical vertebrae not as elongated as in the giraffe.
  • Five sacral (lower back) vertebrae (3-4 in giraffe)
  • Only three tarsal (ankle area) bones; giraffes have four tarsal bones.
  • Unlike giraffe, okapi has glands between toes on all 4 feet.

Pelage

  • Reddish-brown to black, velvety pelage on body and face.
  • Black muzzle and nostrils.
  • Long, thick eyelashes
    • Calf has long hairs around eyes or "false eyelashes" that disappear in time.
  • Tapered white or creamy white horizontal stripes on rear and upper front legs
  • Anklets and stockings of white on lower legs (perhaps enabling other okapi to easily follow through dark forests as they have poor eyesight).
  • Cheeks, throat and rear-most belly are whitish to gray or tan.
  • Newborns have similar color and pelage; mane is conspicuous and is largely lost by adulthood
  • Hairs of white stripes are longer than hairs in dark stripes

Sexual Dimorphism

  • Males have skin-covered horns
  • Females have no horns but do have "bumps" or hair whorls on head where horns would be; occasionally have rudimentary horns.

Other Physical and Physiological Characteristics

Genetic characteristics

  • Okapis have unusual chromosome numbers; rather the normal 46 chromosomes, numbers may be 45 or even 44 (Lindsey et al 1999)
    • In other animals such variations are abnormal or fatal; okapis with such numbers are otherwise normal.
  • Hybrids of okapis with other species not known.

Okapi

Okapi head

Almost nothing is known about okapi anatomy and physiology.

Note the skin-covered ossicones. These show the okapi is related to giraffes, which also have these permanent horn-like projections.

Image credit: © San Diego Zoo Global. All rights reserved.

Page Citations

Bodmer & Rabb (1992)
Colbert (1938)
Dagg & Foster (1982)
Grzimek (1990)
Hart (2013)
Lindsey et al. (1999)

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