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Gelada (Theropithecus gelada) Fact Sheet: Physical Characteristics

Physical Characteristics

Body measurements (summarized from Bergman and Beehner 2013)

MaleFemale
Body Weight 16.5-20.5 kg (36.4-45.2 lb) 8.3-13.8 kg (18.3-30.4 lb)
Head and Body Length 690-740 mm (2.3-2.4 ft) 500-650 mm (1.6-2.1 ft)
Tail Length 460-500 mm (1.5-1.6 ft) 320-640 mm (1.0-2.1 ft)

General Appearance

Body shape (from Bergman and Beehner 2013 unless otherwise noted)

  • Large-bodied, terrestrial primate
    • Similar in size and appearance to true baboons (Papio spp)
  • Head
    • Skull large with a deep, massive muzzle
    • Ears concealed by hair (Hill 1970)
  • Limbs
    • Moderately long (Hill 1970)
  • Tail
    • Medium-length, shorter than in true baboons
    • Tuft of hair at tip

Facial characteristics (from Bergman and Beehner 2013 unless otherwise noted)

  • Facial hair
    • Minimal hair on the face
    • Grayish hair often surrounds the face
  • Skin
    • Black
  • Eyes
    • Lids whitish or pale pink
      • Sharply contrasts with the black face when the brow is retracted in aggression
  • Muzzle
    • Projects forward, though less so than in true baboons
    • Rounded at end
    • Dorsal surface concave, with a longitudinal (along its length) series of folds (Hill 1970)
  • Lips (Hill 1970)
    • Deep
    • Upper lip highly mobile
  • Cheeks
    • Indented
  • Neck
    • Red hour-glass shaped area of bare skin
    • Extends onto the chest
    • Color intensity is variable
      • Age, reproductive stage, recent activity, and social position affect hue

Adult pelage (from Bergman and Beehner 2013 unless otherwise noted)

  • Hair
    • Coarse and wiry (Hill 1970)
    • Long, thick, golden mane (mantle or cape) on adult males
  • Back
    • Pale, brown to near black
    • Tinged with gold, red, and gray tones
  • Hands and feet
    • Elongate (Hill 1970)
    • Black nail on each finger (Vram 1923)
    • Pads naked and black (Hill 1970)
  • Buttock
    • Hairless
    • Black, calloused
    • Four-lobed ('four-leaf clover') appearance

Sexual Dimorphism

Highly dimorphic (from Crook 1966 unless otherwise noted)

  • Body size variation
    • Adult males c. two times heavier than adult females
  • Appearance
    • Adult male
      • Hairy cape that extends to the shoulders (description above)
      • Canine teeth enormous
    • Adult female
      • Coat color more uniform (Bergman and Beehner 2013)
      • Lack cape (Bergman and Beehner 2013)
      • Skin of neck and chest pale pink, ringed with vesicles that swell to indicate the preovulatory period (Bergman and Beehner 2013)
        • Brighter red when in estrus or pregnant (Bergman and Beehner 2013)
      • Superficially similar to macaques

Adaptations

Foraging adaptations

  • Hands and fingers
    • Thumb elongated and index (2nd) finger abbreviated (from Bergman and Beehner 2013; Jablonski 1993 unless otherwise noted)
      • Together enable pincer-like grip; aids in picking grass leaves
      • Highest degree of thumb opposability of any non-human primate
  • Padded buttocks (Bergman and Beehner 2013)
    • Calluses and pads on hind-end facilitates 'scooting' along the ground during foraging
  • Dental specialization
    • Molar (teeth) specialized to resist wear and provide a grinding surface (Dunbar and Bose 1991)
      • High crown with enamel extending below the gumline
      • Deep surface grooves

Other Characteristics

Chromosome number

  • 21 pairs of chromosomes (2n=42) (Chiarelli 1962)

Subspecific characteristics (from Bergman and Beehner 2013 unless otherwise noted)

  • Northern gelada (Theropithecus gelada gelada)
    • Mane pale brown to chocolate
    • Thin, iron-gray hair surrounds skin patch on chest
  • Southern gelada (T. g. obscurus)
    • Mane dark chocolate to near black
    • Extensive, pure-white hair surrounds skin patch on chest
      • Extends onto the inner sides of upper arms

Similar primates (from Bergman and Beehner 2013)

  • Hamadryas baboon (Papio hamadryas)
    • Live within the range of geladas
    • Pale face, red buttock, and light-colored hair distinguish this species
    • Lack bare, red throat and chest patch
  • Olive baboon (Papio anubis)
    • Live within the distribution of geladas
    • Lack of hair tuft at tip of tail distinguishes this species
    • Lack bare, red throat and chest patch

Striking Physical Appearance


Geleda red chest hair

Geladas are easily identified by the bright-red, hour-glass shaped, exposed skin on their neck and chest. Adult males are nearly two times heavier than females and sport a cape (mane) of hair which extends to their shoulders.

Image credit: © Waddington from FlickrSome rights reserved.

Page Citations

Bergman and Beehner (2013)
Chiarelli (1962)
Crook (1966)
Dunbar and Bose (1991)
Hill (1970)
Jablonski (1993)
Vram (1923)

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