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Giant Panda (Ailuropoda melanoleuca) Fact Sheet: Reproduction & Development

Update in Progress

Dear Readers,

Some of the information in this fact sheet, like a panda, has become fuzzy. San Diego Zoo Wildlife Alliance is working to bring you an updated version of the Giant Panda Fact Sheet with additional science and conservation information. Thanks for your patience, as we quietly leaf through the research literature.

Please check back soon. SDZWA team members can email questions to library@sdzwa.org.

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Courtship

Polygynous mating

  • One male with two or more females (Reid & Gong 1999); multiple females sequentially ("scramble competition polygyny") (Swaisgood et al. 2016)
  • Strong competition for access to females mating season (Schaller et al. 1985)
    • Brief, spring mating season
    • Courting pair often attracts more males, creating a competitive/combative situation
      • Viewing competition may be vital for female's receptivity
  • Details of male reproductive strategy (Nie et al. 2012)
    • Intense male competition for females about to be fertile
    • After dominant status is established among males, aggression declines
      • Testosterone levels do not correlate with levels of aggression or with outcomes of competition
      • Large body size was primary reason a male became dominant

Courtship

  • Scent marking, visual displays and vocalizations important in advertising to and assessing potential mates (Owen et al. 2013; Wei et al. 2015)
    • Individuals produce bleating sounds
      • Appear to rely more on sound to coordinate mating than other bears (Stirling and Derocher 1990)

Mating season

  • Late February to early April

Female behavior

  • Social conditions influence how some female pandas communicate reproductive status (Owen et al. 2016)
    • Use odor in presence of other females; use sound and visual displays when few females nearby

Reproduction

Reproductive success

  • High reproductive rates in the wild (Pan et al. 2014, Swaisgood et al. 2016)
    • Pandas in managed care judged harshly as showing little interest in mating
  • Lifetime reproduction
    • A single female capable of producing c. 5-10 litters in her lifetime (Wildt et al. 2004)
  • Factors effecting reproduction
    • Food supply available to mother
    • Presence of young
      • Lactation suppresses estrus

Estrus

  • Duration
    • Lasts 1-3 weeks with peak receptivity from 2-7 days
  • Occurs March-May
    • Females without young may also go into heat in September - October

Fertilization and implantation

  • Delayed development and implantation of embryo
    • Development of the fertilized egg may be suspended
    • Implantation in the uterus can also be delayed

Gestation and birth

  • Gestation
    • Duration highly variable
      • Ranges 84-184 days
      • Average 138.6 ± 19.8 (Zhu et al. 2001)
  • Timing of birth
    • Usually occurs August-October
  • Mother's behavior prior to birth
    • Female may descend to lower elevations in the wild (Zhu et al. 2001)
      • Often followed by reduced levels of activity (Zhu et al. 2001)
  • Mother's behavior after birth
    • Begins to fast, as occurs in other bears
      • One mother was observed to neither feed or defecate for 25 days
      • Both managed and wild females exhibit this behavior, which seems unrelated to availability of food
    • She does not leave infant
      • Mother remain with infant continually to keep it warm
  • Litter size
    • 1-2 cubs (very rarely 3)
      • Only one cub is raised in wild; reports of twins being reared not well documented
        • It is extremely difficult for a female panda to hold, suckle and carry 2 young and eat extra bamboo
      • Managed care breeding now successfully removes one cub, and switches out the twins to give both a chance for mother's care and milk
  • Denning (Zhu et al. 2001) (Zhang et al. 2007b)
    • Not having adequate den sites may limit population growth by pandas
    • Female gives birth in a den (rock cave or hollow tree)
      • Often close to water (Swaisgood et al. 2016)
    • Birthing nest is of simple construction with little bedding
    • Females occupy several dens as the cubs grow
    • Reducing exposure to parasites and predators may explain use of several dens
    • Dens abandoned when cub is around 94 days old and can thermoregulate (Zhu et al. 2001)
      • Mothers abandon dens around 112 days after birth

Interbirth interval

  • Do not reproduce annually
    • c. 2.2 years for pandas studied in wild (Pan et al 2001) (Garshelis 2004)

Infant characteristics

  • Appearance of newborn
    • Pink and naked with sparse covering of white hair
      • At 8-10 days, skin turns gray in areas where fur will be black (Zhu et al. 2001)
    • Tail at birth disproportionately long (1/5-1/3 body length)
    • Eyes closed, don't open fully until 75 or 76 days (but other reports cite 35-48 days; Zhang et al. 1996)
  • Size of newborn
    • Extremely small and the most helpless of all placental mammals (85-140 grams/3-5 oz) (Zhu et al. 2001)
      • Size of all newborn bears is quite small compared to the mother's weight
        • A black bear cub, for example, is only 0.36% of the mother's weight
      • Pandas are the extreme example of this trend
        • A cub, for example, may be only 0.12 % of mother's weight

 

Life Stages

Birth - Infant (1.5 years) (Schaller et al. 1985)

  • Interaction with mother
    • A wild infant spends almost all its time for first weeks directly on mother's body
    • Cubs squall loudly and often in first 2 or 3 months
    • Mother uses mouth rather than a clumsy paw to pick up newborn (Swaisgood et al. 2003)
    • Mother stimulates waste elimination by young cub by licking anogenital area and consumes all waste to eliminate smells and thwart predators
    • Infants suckle often, 6-14 times/day, for up to 30 minutes each time
    • Infants remain with mother up to 18 months
  • Developmental milestones
    • Crawling attempts begin at 2 months
    • Eyes fully open between 2 - 3 months
    • Teeth begin to erupt in 3rd month (Edwards et al. 2006)
    • Begin to vocalize less around 3 months; mothers become less responsive (Swaisgood et al 2003b)
    • Begin walking efficiently until 3 - 5 months
    • Begin to sample bamboo around 5 - 6 months (Edwards et al. 2006)
    • Fully weaned at 18-24 months in wild (Edwards et al. 2006b)

 

Sub adults: 1.5-5 years

  • Juveniles travel with mothers until about 18 months (Schaller et al. 1985)
  • Thought that higher mortality occurs among subadults and females (Li et al. 2017)

Adults:  (Howard et al. 2006)

  • Males are of reproductive age from around 6 to 26 years
  • Females can reproduce between 6 and 20 years

Typical Life Expectancy

Wild populations

  • Not reported

Managed care

  • No AZA estimates

Panda Reproduction and Development

Giant panda baby

A giant panda mother holds her newborn cub against her body.

Giant panda and cub

Cubs develop slowly. Teeth begin erupting during the third month but nursing continues for 8 or 9 months.

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

Page Citations

Garshelis (2004)
Howard et al. (2006)
Nie et al. (2012)
Owen et al. (2016b)
Pan & Lü (1993)
Reid & Gong (1999)
Schaller et al. (1985)
Snyder et al. (2004)
Swaisgood et al. (2003b)
Zhang et al. (2007b)
Zhu et al. (2001)

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