Giraffes (Giraffa spp.) Fact Sheet: Reproduction & Development

Assessing reproductive receptivity

• Solitary male checks females in a herd by testing odor of hind parts or urine ("Flehmen" response).
• Includes lip curl, which helps to bring odor to vomeronasal organ.
• Dominant male often guards the estrus female from other males.
• He is usually the only male in a given area that will get to mate.

Courtship and mating

• The male signals his readiness to mate by tapping on the female's hind leg with his foreleg or resting his chin on her back.
• He usually follows her, sometimes for hours, until she allows him to mount her.
• No long term bonds seem to form between the male and female.
• Little known about influences on male mating success, female mate choice, the number of males females copulate with, or offspring paternity (Bercovitch and Deacon 2015).
• Females will canter away to avoid a courting male (Seeber et al. 2012).

Breeding cycle

• Estrus cycle: 15 days
• Breeding occurs throughout the year (Bercovitch and Berry 2009b).
• Births occur throughout the year, though some occur seasonally (Dagg 2014)
  • May be influenced by rainfall, food availability, and other conditions helpful to female giraffe.
  • Possibly nutritional advantages related to season; see Lee et al. (2017)
• Females can become pregnant again while lactating, an unusual trait for large mammals (Bercovitch and Berry 2009b).

Gestation

• Age of first parturition: 6-7 years old (wild giraffe) (Bercovitch and Berry 2009b; Berry and Bercovitch 2012)
  • May be earlier in managed care, possibly due to environmental factors such as diet quality.
• Maximum age at last parturition: 24 years old (wild giraffe) (Bercovitch and Berry 2009b; Berry and Bercovitch 2012)
• Pregnancy: 446-457 days, on average (Dagg 2014)
• Litter Size: 1, rarely 2
• Interbirth interval: 19-22 months on average (similar for wild and captive giraffe) (Leuthold and Leuthold 1978; Bercovitch and Berry 2009b; Bercovitch and Deacon 2015)
  • Highly variable
  • Not thought to be affected by infant survivorship (Bercovitch and Berry 2009b)

Birth

• Weight of calf at birth: ~100 kg (220 lbs) (wild giraffe) (Skinner and Hall 1975; Wilson and Mittermeier 2011)
  • Neonate wild giraffe heavier than captive giraffe (Skinner and Hall 1975)
• Shoulder height of calf at birth: 1.5-1.8 m (4.9-5.9 ft) (Wilson and Mittermeier 2011)
• Females give birth standing up.
• Newborns drop to the ground.
• Newborns are able to stand about 5-20 minutes after birth.
• Begin suckling within an hour (Dagg 2014).
  • Milk high in protein and fat
  • Lactating females produce 2.5-10 liters of milk per day (Wilson and Mittermeier 2011).
  • Colostrum, a first milk after birth, confers immunity from some diseases to a calf.
• Females tend to return to the same calving area for successive births.
• Females give birth alone and remain alone with their calves for a week or more, protecting calves from predators and avoiding other giraffes.

  Infant (< 1 year old)

• Predator defense
  • When too young to defend themselves, calves remain still, lying on the ground, hiding (Toon and Toon 2004).
  • Mother is often at least 10-25 meters (33-82 ft) away.
  • Will often leave the calf alone for several hours at a time, as she travels to water.
  • Mother also actively defends calf against predators, like lions.
    • Lions may lunge at nursing females to distract females from their calves (Strauss and Packer 2012).
• Crèches
  • After 1-4 weeks, calves may begin grouping together in crèches, with mothers standing watch for predators and other dangers.
  • At this time, many mothers will leave for long periods to browse.
  • They will return to feed their young before dark and stay through the night.
  • Sometimes, a few females stay behind to care for the young, but young can be left alone for several hours.
• By 3-4 months of age
  • Calves begin browsing and ruminating.
  • Reports of calves tasting leaves when only 3 weeks old.
• At about 4-6 months, calves begin to feed with the female herd.

Juvenile

• Weaning age varies (6-17 months), but most commonly begins at 9-12 months (wild giraffe) (Langman 1977).
• Independent of mother by two years of age, but some association may last longer (especially among females).
• Males tend to wander farther, at a younger age, than females.
• No difference in behavior or development among subspecies has been reported.

Adult

• Maturity (wild giraffe)
  • Females: 4-5 years
  • Males: about 9-10 years (varies: 8-11 years) (Bercovitch and Berry 2012; Berry and Bercovitch 2012)
• Horn development
  • Horns fully developed at 4-4.5 years in males and 7 years in females.
  • Cartilaginous bumps grow and begin to ossify (become bony) starting at the tip, eventually merging with skull.
  • Forehead becomes more heavily ossified, forming an additional knob in front of main horns.
    • Present in both males and females, but the knob on the male may develop into what looks like a third horn.
  • Males: Bony growth continues all over front of skull, including forehead, over the eyes, and on the nose. Much more dense than that of females.

Wild populations

• 1970s research literature: Suggests giraffes commonly live 15-20 years (Foster and Dagg 1972; MacClintock 1973)
• 2012 longitudinal study of male Thornicroft's giraffe by Berry and Bercovitch:
  • Males: average life expectancy of 14-16 years
    • Reduced life span of males attributed to larger body size
      • Female giraffe are 2/3 to 1/2 the body mass of males (giraffes are a size-dimorphic animal)
  • Females: average life expectancy not reported

Managed care

• Median life expectancy (AZA 2024)
  • Males: 15.1 years
  • Females: 20.2 years
• Females live 25% longer than males (Lackey and LaRue 1997)

Lion predation

• Direct observations of attacks by lions are rare (Strauss and Packer 2013).
• Intensity of lion predation varies by area (also see Brenneman et al. 2009).
• Giraffes are an important food source for lions in some areas. Elsewhere, lions likely prefer smaller or more abundant prey, such as zebra, buffalo, antelopes, and wildebeest (Hayward and Kerley 2005; Davidson et al. 2013; Strauss and Packer 2013).
• Attacks with contact are infrequent.
• Giraffes defend themselves with front and rear kicks.
• Lions may leave claw marks (scars) on a giraffe's hindquarters.
• Only a portion of attacks are fatal.
• Predation by lions on calves less than a year old may be intense. Mortality may be high, up to 45-50% (or perhaps higher) in the first year of life (Bercovitch and Berry 2009a, 2009b; Strauss and Packer 2013).
• An exception is the West African giraffe, G. c. peralta, which does not have natural predators (Suraud et al. 2012).
• Predation by lions drops off substantially after the first year; still attack subadults and adults (Strauss and Packer 2013).

Other predators

• Hyenas, leopards, and wild dogs (Toon and Toon 2004)

Malnutrition

• Possible food shortages or poor food quality (Brenneman et al. 2009; Giraffe Conservation Foundation 2013)
• Caused by drought, disruption of migration routes, other spatial restrictions, or intense browsing pressure
• Of particular concern during the dry season

Diseases (Giraffe Conservation Foundation 2013)

• Anthrax
• Rinderprest

Hunting by humans

• See Threats to Survival.
• Bushmeat trade
• Rentsch and Packer (2015): Giraffes accounted for less than 3% of carcasses located during anti-poaching patrols.

A 16-day old male Masai giraffe at the San Diego Zoo Safari Park. He was 6 feet, 6 inches tall at birth; when full grown, he could stand as tall as 19 feet.

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

Bercovitch and Berry (2009a)
Bercovitch and Berry (2009b)
Bercovitch and Deacon (2015)
Berry and Bercovitch (2012)
Brenneman et al. (2009)
Dagg (2014)
Estes (1991)
Foster and Dagg (1972)
Innis (1958)
Lackey and LaRue (1997)
Leuthold (1979)
Leuthold and Leuthold (1978)
MacClintock (1973)
Nowak (1999)
Rentsch and Packer (2015)
Seeber et al. (2012)
Spinage (1968)
Strauss and Packer (2013)
Toon and Toon (2004)