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Grevy's Zebra (Equus grevyi) Fact Sheet: Reproduction & Development

Courtship

Female receptivity

  • Receptive 2-3 days of an estrus cycle
    • Estrus lasts 5-10 days
    • When ready to mate, estrous female raises hind quarters, tail to one side, ears back, with open-mouth

Male behavior

  • Males often display with ears back and bare teeth during mating
    • Possibly to intimidate other males or the female
  • Mounting
    • Male may attempt to mount, even if female moves away

Reproduction

Non-seasonal reproduction

  • Sexes live apart until environmental conditions are favorable for reproduction
  • Male reproductive success correlates only with quality of resources
    • Size of an individual does not effect reproductive success

Gestation & Birth

Gestation

  •  Duration
    • 390 days; longest of any equid
      • Variation noted in managed and semi-managed populations (387-428 days)

    

Birth (from Churcher 1993)

  • Mother's behavior
    • Female stays with foal, away from other females, for 1-2 days
    • Mother and foal rejoin the group once imprinting is complete
      • Foal imprints on mother's scent, call, and stripe pattern
  • Timing of birth
    • Young typically born in August or September in the wild
  • Foal characteristics
    • Weight at birth: about 40 kg (88 lbs)
    • Foal stands within 10 minute; runs within about 45 minutes

Life Stages

Infant (< 1 year old) (from Churcher 1993 unless otherwise noted)

  • Development
    • Nursing lasts for 75% of the first year, or about 9 months
    • Legs are so long, young foal must spread them to touch the ground (Estes 1991)
    • Front-most milk teeth erupt by 1-week old.
    • Striping is light brown at first, becomes sepia with age
  • Foal mortality in wild may be as high as 50%
    • Mother may leave foal unattended during dry season while searching for water
    • Young do not hide as do many hoofed animals; remain standing
    • Young very conspicuous and vulnerable to predation at such times

Juvenile (Churcher 1993)

  • First permanent molars erupt at 1 year

Subadult (from Churcher 1993)

  • Development
    • Third molar teeth are in place at 2.5 yrs
    • Young zebras follow mothers up to about 3 years

Adult (from Churcher 1993)

  • Males reach puberty at 4 years when all permanent incisors have erupted
    • Can reproduce up to 18 years
    • In wild, stallions are sexually mature at about 6 years
    • Puberty not an indicator of breeding activity in wild; young males can not compete with older stallions
    • Some males may never become breeding adults
  • Females reach puberty at 3-4 yrs when permanent incisors are erupting

Longevity

Longevity in managed care

  • 22-30 years

Grevy's Zebra Foal

two Grevy Zebra running

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.

Page Citations

Churcher (1993)
Ginsberg (1989)
King (1965)
Kingdon (1975)
Sundaresan et al (2007)

SDZWA Library Links