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Western Lowland Gorilla (Gorilla gorilla gorilla) Fact Sheet: Reproduction & Development

Courtship

  • Not observed for western gorillas in the wild.
  • Females in Virunga National Park, Democratic Republic of the Congo, and in managed care have provided information on receptivity.
    • First mating ~7.5 years
    • First conception ~8.5 years
  • Adult females mate with silverback on different days
  • Copulations occur during travel-feed periods

Reproduction

Sexual Maturity: Age at first reproduction not yet measured at any Western site. Following data based on Mountain gorillas and gorillas in managed care.

  • Male: Complete copulation by age 9-10 years but few mating opportunities until Silverback status ~ 12-15
  • Female: Perineal tumescence observed in the field ~5.7-7.1 years
    After 2 years of adolescent sterility, first birth - 8.5-10 years.

Estrus cycle: estrus period = 1-2 days, 22-38 day cycle.
First pregnancy: 8.5-10 years
Gestation: 251-295 days
Young per birth: 1, twins rare
Reproductive Rate: 3.5 - 4.5 year birth interval
Infant mortality: varies depending on group 8%-43%

Life Stages

  • Develop twice as fast as humans
  • Infants (0-3 years)
    • Crawl at 3 months
    • Begin eating some plants at 2.5 months
    • 4-6 months - run on all fours
    • Climb at 6-7 months
  • Weaning - 3 years+
  • Juveniles (3-6 years)
  • Sub-adults (6-8 years)
  • Adult female > 8-10 years
  • Blackbacks / adult males (8-11 years) Silvering of hair begins around age 10.
    • 18 years to reach full maturity
  • Young silverbacks (12-15 years)
  • Silverbacks >15

Longevity

Western Lowland Gorilla

mom and baby

Western Lowland Gorilla and infant.

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

 

mom and baby

A three-week-old Western lowland gorilla observed his surroundings as he was held by his mother (San Diego Zoo, 2015).

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

Page Citations

Robbins, (2004)
Maple & Hoff, (1982)
Watts, (1991)
Grzimek, (1990)
Fossey, (1982)

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