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Platypus (Ornithorhynchus anatinus) Fact Sheet: Summary

Platypus (Ornithorhynchus anatinus) Fact Sheet

Side profile of platypus swimming at Taronga Zoo

Platypus (Ornithorhynchus anatinus)

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.
Image location: Taronga Zoo, Sydney

Taxonomy Physical Characteristics

Kingdom: Animalia

Phylum: Chordata

Class: Mammalia (Linnaeus, 1758) — mammals

Order: Monotremata (Bonaparte, 1837) — monotremes (egg-laying mammals)

Family: Ornithorhynchidae (Gray, 1825 sensu Burnett, 1830)

Genus: Ornithorhynchus (Blumenbach, 1800)

Species: Ornithorhynchus anatinus (Shaw, 1799) – platypus, duck-billed platypus

Body Weight
Male: 0.8-3.0 kg (1.8-6.6 lb)
Female: 0.6-1.7 kg (1.3-3.7 lb)

Head-body Length (tip of bill to tip of tail)
Male: 40-63 cm (16-25 in)
Female: 37-55 cm (15-22 in)

Thick fur that provides insulation against cold water while swimming.
Upperbody dark brown to reddish-brown. Underbody pale brown to silvery-cream.

Distribution & Status Behavior & Ecology

Native to eastern mainland Australia, Tasmania, and King Island. Introduced to western Kangaroo Island.

Freshwater streams, lakes, pools, and associated wetland/riverine (riparian) zones

IUCN Status
Near Threatened (2014 assessment)

CITES Appendix
Not listed

Other Designations
Protected in Australia.
Endangered in South Australia.

Populations in the Wild
No rigorous estimates. Considered common within its range but populations undergone large declines since 1890s. Possibly numbers in the thousands or tens of thousands (roughly 30,000 to 300,000).

Use powerful forelimbs for swimming and burrowing. Rear limbs act as rudders while swimming.

Activity Cycle
Mainly nocturnal. Rest in burrow during the day. Forage at night. Sometimes active during the day.

Social Groups
Solitary outside of breeding season.

Mainly bottom-dwelling insects (especially larvae). Also, shrimp, crayfish, and swimming insects. Other occasional prey.

Not well known. Red fox, domestic and feral dogs, cats, Tasmanian devil, raptors (e.g., wedge-tailed eagle).
Infrequently, crocodiles and large native fish. Possibly goannas and snakes.

Reproduction & Development Species Highlights

Sexual Maturity
Physical maturity reached at two years of age. Many individuals begin breeding later.

Mating System
Likely polygynous. Confirmation needed.

Approximately 21 days

Incubation period
Approximately 10 days

Litter Size
1-3 eggs per breeding season; 2 eggs most common

Birth Weight
Not known

Age at Weaning
About 3-4 months

Typical Life Expectancy
Wild populations: typically 7-14 years, but may be lower in degraded habitat areas

Feature Facts

  • Distinctive bill—unique among mammals
  • Hunt by detecting minute electric fields of prey with sensitive bill
  • Often forage 10 to 12 hours per day; longer in some locations and seasons
  • Females lay eggs
  • Females lack nipples; milk exuded through skin patches
  • Properties of platypus milk may protect hatchlings against infections
  • Adult males have venomous spurs—likely to defend mates and territory from rival males (unusual adaptation among venomous animals)
  • Thick fur provides exceptional insulation against cold water (better than that for polar bears and beavers); thick fur makes platypuses prone to heat stress when out of the water.
  • Not easily seen by humans in the wild
  • Difficult to keep and breed in managed care settings
  • Few platypuses in zoos; currently, two reside at the San Diego Zoo Safari Park, all others in Australian collections

About This Fact Sheet

For detailed information, click the tabs at the top of this page.


© 2018-2019 San Diego Zoo Wildlife Alliance. Minor updates to Population & Conservation, Cultural History, Taxonomy Jul 2019.


How to cite: Platypus (Ornithorhynchus anatinus) Fact Sheet. c2018-2019. San Diego (CA): San Diego Zoo Wildlife Alliance; [accessed YYYY Mmm dd]. platypus.
(note: replace YYYY Mmm dd with date accessed, e.g., 2015 Sep 10)


Disclaimer: Although San Diego Zoo Wildlife Alliance makes every attempt to provide accurate information, some of the facts provided may become outdated or replaced by new research findings. Questions and comments may be addressed to


Thank you to Josh Griffiths for providing expert content review of this fact sheet.

Senior Wildlife Ecologist Josh Griffiths leads cesar australia’s platypus ecology research team, including field studies to monitor platypus abundance, distribution, and population recovery, as well as ecological genetics. He is also deeply involved in cesar australia’s community engagement initiatives, such as platypusSPOT, a citizen science project.

Mr. Griffiths has extensive experience studying platypuses in the wild, including conducting field surveys of platypus abundance and health. He also works with government representatives, industry leaders, and community members to develop management plans and conservation programs related to the platypus.

Mr. Griffiths has worked in diverse landscapes in arid South Australia, the highlands of Victoria, and Tasmania’s river systems. Mr. Griffiths earned his bachelor’s degree in Environmental Biology the University of Adelaide. See his detailed profile on cesar australia’s website.

Thank you to Dr. Jessica Thomas for providing expert content review of the Managed Care section of this fact sheet.

Senior Keeper Dr. Jess Thomas oversees the platypus husbandry program at Healesville Sanctuary, a world-renowned facility in platypus breeding, care, and research. In 2018, Dr. Thomas earned a PhD from the University of Melbourne, where she studied platypus breeding behavior. She also investigated maternal care and juvenile dispersal in the platypus.

As a keeper, Dr. Thomas oversees Healesville’s platypus managed care programs, including behavior, diet, nutrition, health, and exhibit environment. She has conducted research on behavioral enrichment for platypuses to enhance animal welfare in zoos. Dr. Thomas is the platypus studbook keeper as well as a species coordinator for the Zoo Aquarium Association.

Thank you to Dr. Thomas H. Rich, Curator of Vertebrate Palaeontology at Museums Victoria, for reviewing the Evolutionary History section (in Taxonomy & History) of this fact sheet. Dr. Rich has extensive research experience with extinct monotremes and other extinct mammals. See his Museums Victoria curriculum vitae and publications list to learn more.

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