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Orangutans (Pongo spp.) Fact Sheet: Population & Conservation Status

Population Status

Bornean orangutans (Pongo pygmaeus)

  • Not precisely known (IUCN)
    • 55,000-104,000 individuals
      • Loss of 50% of historic population in only 40 years
  • Between 1996 and 1997 the population dropped by 33% due to fires and drought (Rijksen & Meijaard 1999) (Delgado & Van Schaik 2000)
  • Estimates obtained between 2000 and 2003 indicate between 45,000 and 69,000 individuals, but rapidly declining since then (Singleton et al. 2004)
  • Populations on Borneo possibly have "lower mortality, faster breeding, more capacity for rapid population growth" when compared to those of Sumatran orangutans (Singleton et al. 2004)
  • Habitats need to support populations of at least 250 individuals to allow genetic stability and stable populations (Singleton et al. 2004)
  • Rates of hunting over 3% a year will drive any population to extinction, even in good habitats (Singleton et al. 2004)

Sumatran Orangutans (Pongo abelii)

  • Population is much smaller than that in Borneo, approximately 14,000 individuals (IUCN)
  • Experienced a population decline of over 80% in the last 75 years (Singleton et al. 2008)
  • Population in 2000 estimated at 12,500 individuals; approximately 14% of the estimated population from 1900.
  • According to the IUCN SSC Conservation Breeding Specialist Group (Singleton et al. 2004) "populations may decline by 50% in about a decade, by 97% in 50 years, and will eventually disappear unless continued habitat loss is stopped"

Tapanuli Orangutans (Pongo tapanuliensis)
(Narter et al. 2017)

  • Fewer than 800 individuals in the wild
  • Of high conservation concern
    • Small population size
    • Geographically isolated

Conservation Status

IUCN

CITES

  • Pongo abelii: Appendix I (UNEP 2019)
  • Pongo pygmaeus: Appendix I (UNEP 2019)
  • Pongo tapanuliensis: Not listed (UNEP 2019)​

Other protections

  • Protected under some domestic legislations in Indonesia

Threats to Survival

Habitat loss and fragmentation

  • Orangutans' arboreal lifestyle makes them extremely vulnerable to habitat fragmentation and tree loss
  • Borneo and Sumatra: logging, clearing for cash crops, human population pressure, fires, drought
    • In Sumatra, an estimated 1,000 orangutans were lost because of forest loss each year in the 1990's;
    • In Sumatra, new political stability since 2005 has allowed many new logging and palm oil concessions (Singleton 2008)

Hunting by humans

  • For the pet trade and for food

Political unrest

  • Disturbance, loss of habitat
  • Difficult to implement conservation strategies

Other notes

  • Slow reproductive rate makes the orangutan more vulnerable to long-term disturbance

Clyde

an orangutan

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

Page Citations

Delgado & Van Schaik (2000)
Hutchins, et al., (2001)
Rijksen & Meijaard (1999)
Rijksen, (2001)
Singleton et al., (2004)
Singleton et al, (2008)

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