Ornithorhynchus anatinusduck-billed platypus

Geographic Range

The geographic range of Ornithorhynchus anatinus is restricted to the wetter regions of eastern Australia and Tasmania. (Grant and Temple-Smith, 1998; Pasitschniak-Arts and Marinelli, 1998)


Duck-billed platypuses inhabit rivers, lagoons, and streams (Pasitschniak-Artsand Marinelli, 1998). They prefer areas with steep banks that contain roots, overhanging vegetation, reeds, and logs (Grant and Temple-Smith, 1998). The rivers and streams are usually less than 5 meters in depth (Grant and Temple-Smith, 1998). There have been records of them living in aquatic habitats at elevations above 1000 meters (Grant and Temple-Smith, 1998). (Grant and Temple-Smith, 1998; Pasitschniak-Arts and Marinelli, 1998)

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams
  • Range elevation
    1000 (high) m
    3280.84 (high) ft
  • Range depth
    5 (high) m
    16.40 (high) ft

Physical Description

Duck-billed platypuses are one of three species of monotremes. These species are unique among mammals in that they retain the ancestral characteristic of egg laying. They have a cloaca through which eggs are laid and both liquid and solid waste is eliminated. Duck-billed platypuses are stream-lined and elongated, they have fur ranging from medium brown to dark brown on the dorsal side and brown to silver-gray on the ventral side. They have bills that closely resemble those of ducks, and flat and broad tails resembling those of beavers (Grant and Temple-Smith, 1998). Two nostrils are located on top of their bills and their eyes and ears are on either side of their heads. They have short limbs, naked soles, webbed forefeet and partially-webbed hind feet. Each foot contains five digits each consisting of a broad nail for the forefeet and sharp claws for the hind feet. Males are generally larger than females, and have two venom glands attached to spurs on their hind legs. Females have mammary glands but no nipples. The young have milk teeth while the adults have grinding plates. The young are smaller than adults in size. There is a significant reduction in body fat after winter for both young and adults (Pasitschniak-Arts and Marinelli, 1998). (Grant and Temple-Smith, 1998; Pasitschniak-Arts and Marinelli, 1998)

  • Range mass
    0.8 to 2.5 kg
    1.76 to 5.51 lb
  • Average mass
    1.52 kg
    3.35 lb
  • Range length
    390 to 600 mm
    15.35 to 23.62 in
  • Average length
    465 mm
    18.31 in
  • Average basal metabolic rate
    468 cm3.O2/g/hr
  • Average basal metabolic rate
    1.931 W


Male duck-billed platypuses initiate most mating interactions but successful mating relies entirely on the willingness of females. Mating is seasonal and varies with population. Male and female platypuses touch as they swim past each other. The male grabs the tail of the female with his bill and if the female is unwilling, she will try to escape by swimming through logs and other obstacles until she is set free. However, if she is willing, she will stay near the male and will allow him to grab her tail again if he dropped it. The male then curls his body around the female, his tail underneath her to one side of her tail. Then he moves forward and bites the hair on her shoulder with his bill. Other details of the mating patterns of platypuses are mainly unknown due to their secretive, aquatic nature. There is a higher proportion of spur wounds in males than females, which may be explained by aggressive encounters between males during mating season. (Grant and Temple-Smith, 1998; Pasitschniak-Arts and Marinelli, 1998)

Duck-billed platypuses are one of the three mammal species that lay eggs. There is little available information on breeding, estimated gestation periods are 27 days and incubation periods are 10 days. Lactation lasts three to four months. Most juvenile females do not begin to breed until they are four years old (Grant and Temple-Smith, 1998). (Grant and Temple-Smith, 1998; Pasitschniak-Arts and Marinelli, 1998)

  • Breeding interval
    Duck-billed platypuses probably breed once each year.
  • Breeding season
    Duck-billed platypuses breed in late winter or autumn.
  • Range number of offspring
    1 to 3
  • Average number of offspring
  • Average gestation period
    17 days
  • Range weaning age
    3 to 4 months
  • Range age at sexual or reproductive maturity (female)
    2 (low) years
  • Range age at sexual or reproductive maturity (male)
    1.5 (low) years

Female duck-billed platypuses build burrows in which to protect and nurse their young. During the incubation period, the female platypus will incubate eggs by pressing the egg to her belly with her tail. The incubation period usually lasts for 6 to 10 days. Duck-billed platypuses generally lay two to three eggs. ("Duck-billed Platypus", 2008; Grant and Temple-Smith, 1998; Pasitschniak-Arts and Marinelli, 1998)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female


There is little information on the longevity of duck-billed platypuses. They can live up to 12 years in the wild.


Duck-billed platypuses are solitary, especially males. If the territories of males overlap, they change their foraging time to avoid each other. (Grant and Temple-Smith, 1998; Pasitschniak-Arts and Marinelli, 1998)

Home Range

Home range size varies depending on the area, ranging from 0.37-7.0 km. Duck-billed platypuses that forage in streams typically have larger home ranges than those that forage in ponds (Pasitschniak-Arts and Marinelli, 1998). (Grant and Temple-Smith, 1998; Pasitschniak-Arts and Marinelli, 1998)

Communication and Perception

Duck-billed platypuses make some sounds, but their role in communication hasn't been defined yet (Pasitschniak-Arts and Marinelli, 1998). (Grant and Temple-Smith, 1998; Pasitschniak-Arts and Marinelli, 1998)

Food Habits

Duck-billed platypuses eat primarily aquatic invertebrates in streams and lakes (Grant and Tempple-Smith, 1998). They also eat shrimp, fish eggs, and small fish (Pasitschniak-Arts and Marinelli, 1998). (Grant and Temple-Smith, 1998; Pasitschniak-Arts and Marinelli, 1998)

  • Animal Foods
  • fish
  • eggs
  • mollusks
  • aquatic or marine worms
  • aquatic crustaceans


Predators of duck-billed platypuses include foxes, humans, and dogs (Grant and Temple-Smith, 1998). Others are snakes, birds of prey, feral cats, and large eels (Pasitschniak-Arts and Marinelli, 1998).

Ecosystem Roles

There is little information about how duck-billed platypuses affect their ecosystem. However, especially by foraging on aquatic invertebrates, they play an integral role in the food webs of the streams, rivers, and billabongs in which they are found. (Grant and Temple-Smith, 1998; Pasitschniak-Arts and Marinelli, 1998)

Commensal/Parasitic Species

Economic Importance for Humans: Positive

Duck-billed platypus skins were harvested by fur traders to make hats, slippers, and rugs. Harvesting was ended by a law passed in 1912 that protected platypuses from being hunted (Grant and Temple-Smith, 1998). (Grant and Temple-Smith, 1998; Pasitschniak-Arts and Marinelli, 1998)

  • Positive Impacts
  • body parts are source of valuable material

Economic Importance for Humans: Negative

Duck-billed platypuses eat trout (Salmonidae), which are considered a food source for humans. However, trout streams are not privately-owned in Australia so the effect of platypus predation on trouts is neither widely noticed nor regulated. They can harm humans with their venomous spurs if provoked (Grant and Temple-Smith, 1998). (Pasitschniak-Arts and Marinelli, 1998; Grant and Temple-Smith, 1998; Pasitschniak-Arts and Marinelli, 1998)

  • Negative Impacts
  • injures humans

Conservation Status

Duck-billed platypuses are currently protected by the Australian government (Pasitschniak-Arts and Marinelli, 1998). Populations are considered healthy and they are not listed as a species of concern on global conservation lists. (Grant and Temple-Smith, 1998; Pasitschniak-Arts and Marinelli, 1998)


Tanya Dewey (editor), Animal Diversity Web.

Evelyn Ojo (author), University of Maryland, Baltimore County, Kevin Omland (editor, instructor), University of Maryland, Baltimore County.



Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map


uses sound to communicate


young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


an animal that mainly eats meat


uses smells or other chemicals to communicate

  1. active during the day, 2. lasting for one day.

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.


union of egg and spermatozoan


Referring to a burrowing life-style or behavior, specialized for digging or burrowing.


mainly lives in water that is not salty.


offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).


eats mollusks, members of Phylum Mollusca


having the capacity to move from one place to another.


This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.


specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.


active during the night


reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.


having more than one female as a mate at one time


Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

seasonal breeding

breeding is confined to a particular season


remains in the same area


reproduction that includes combining the genetic contribution of two individuals, a male and a female

sexual ornamentation

one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.


lives alone

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"


uses touch to communicate


that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).


Living on the ground.


defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement


the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.


an animal which has an organ capable of injecting a poisonous substance into a wound (for example, scorpions, jellyfish, and rattlesnakes).


movements of a hard surface that are produced by animals as signals to others


uses sight to communicate


2008. "Duck-billed Platypus" (On-line). the Animal Files. Accessed May 07, 2008 at http://www.theanimalfiles.com/mammals/egg_laying_mammals/duck_billed_platypus.html.

Grant, T., P. Temple-Smith. 1998. Field biology of the platypus (Ornithorhynchus anatinus): historical and current perspectives. The Royal Society, 353: 1081-1091.

Pasitschniak-Arts, M., L. Marinelli. 1998. Ornithorhynchus anatinus. Mammalian Species, 585: 1-9. Accessed April 22, 2008 at http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/pdf/i0076-3519-585-01-0001.pdf.