Duck Billed Platypus

SPECIES Duck Billed Platypus
TAXONOMY Ornithorhynchus anatinus
STATUS Near Threatened (RedList.org); Least Concern QLD (ala.org.au); Endangered SA (ala.org.au)

The Duck Billed Platypus, commonly referred to as ‘Platypus’, is unique in the world and native to Australia. Along with the Echidna, it is grouped in a separate order of mammals known as monotremes which are distinguished from other mammals because they lay eggs. When first discovered they caused considerable confusion among European naturalists and thought to be a hoax!

They are found throughout eastern mainland Australia from Far North Queensland to the Australian Alps, and into Tasmania. They are solitary creatures and occur within freshwater systems as they feed within moving streams and shelter in burrows within the banks nearby. They are active year round, sleeping during the day and feeding at night. Their activity is directly related to locality, ambient temperature, daylight, and food availability. 

Appearance
The platypus is well adapted to its semi-aquatic lifestyle. They have a streamlined body, a broad flat tail, and short webbed limbs and partially webbed feet making it an efficient swimmer. They are covered with very dense, waterproof fur which provides excellent insulation. They range in colour from very dark brown to reddish brown with a lighter underbelly, and an adult reaches lengths up to 45 cm and weighs 1.5 kgs. Their skeleton is heavy and similar to that of modern reptiles. The male is slightly larger.

The Duck Billed Platypus has several features uniquely suited to its lifestyle. It is a warm blooded, carnivorous bottom feeder relying on insects, larvae, shellfish, and worms as its main diet often consuming its entire body weight in a single day. The distinctive ‘duck bill’ is used to shovel through the mud to catch its prey, and as it has no teeth - it picks up gravel to grind its food. As it has poor eyesight underwater and hunts mostly at night, it locates its prey with special receptor cells in its bill that detect small changes in electrical fields caused by living organisms.

It has strong claws for burrowing; however the male also sports a 15 mm long venomous spur on the inside of both hind legs. The venom is capable of killing a medium size dog and is dangerous to humans. As it is slow moving and more vulnerable to prey on land, this is a primary defence mechanism. 

Reproduction
The breeding season begins near the end of winter or early spring depending on geography. During this time, the males produce venom which is secreted from the spurs in their hind legs and is used to injure rival males whilst competing for territory and the females that reside there. Females will generally accept the male that is presented as being the biggest and the strongest.

Pairs will engage in a courtship ritual that lasts several weeks. Described as a ‘dance’, they engage in aquatic play, such as diving, rolling together, and even swimming in circles before mating.

She will lay a clutch of up to three leathery eggs deep inside the burrow.  The baby platypus are born underdeveloped. They will lap up milk produced by the mother through folds in her skin. Some have referred to the offspring as a ‘puggle’, adopting the name given to their fellow monotreme species the Echidna. However according to the scientific community, officially they are ‘baby platypus’. 

Threats
Although they spend much of their time in the water or in their burrow, they do fall victim as prey to crocodiles, goannas, large snakes, eagles, foxes, and dingoes. They suffer from parasites which include their own tick species; and in Tasmania they have contracted an amphibian fungal infection that is fatal if it invades the lungs. Habitat destruction and human encroachment pose a threat by limiting range, which leads to a lack of genetic diversity.

The Duck Billed Platypus was once hunted to near extinction due to its highly prized fur. The Australian Government declared it as protected in 1974, and numbers have repopulated. More recently, fishing with nets in freshwater rivers and creeks is now illegal due to the high occurrence of platypus being caught inadvertently in the past. Although no longer considered endangered, it is declared as ‘common but vulnerable. The IUCN (International Union for Conservation of Nature) list it as ‘Near Threatened’.

There is a general lack of knowledge in the species abundance at local catchment levels to predict population trends. They are dependent on established freshwater systems and with human encroachment, this may lead to their decline in the future.

Updated 5 May 2021