Skip to main content

Interesting facts about Australian monotremes ! Platypus on the Australian 20 cent coin

  • Author:
  • Updated date:

Peter has been a animal lover since he was a young lad. He would love to share with you images and stories about Australian Wildlife !


A Platypus depicted in a work of art.

A Platypus depicted in a work of art.

What is a Monotreme?

I must confess that before I started on my Hub on Australian Marsupials, I not only did not know of, or had ever actually heard of the word "monotreme".

OK I hear you ask what is a monotreme, I hope this answers your question.

It is widely accepted that Australia has the only two living examples in the world of the “monotreme”.

Before I show you these examples let me explain about the monotreme.

Monotremes lay eggs. OK big deal I hear you say, so do hens, but wait there IS more, and this is the facinating part.

The egg is retained for some time within the mother, who actively provides the egg with nutrients.

After the baby monotreme breaks away from the egg it is very small and vulnerable but still can find its way up to the mothers mammary glands to suckle.

Monotreme's also lactate, but have no defined nipples, excreting the milk from their mammary glands via openings in their skin.

All species are long-lived, with low rates of reproduction and relatively prolonged parental care of infants.

More interesting facts about Monotremes

The monotremes also have extra bones in the shoulder girdle, including an interclavicle and coracoid, which are not found in other mammals. Monotremes retain a reptile-like gait, with legs that are on the sides of rather than underneath the body. The monotreme leg bears a spur in the ankle region.

The monotremes are the only mammals that do not experience REM sleep.

Their metabolic rate is remarkably low by mammalian standards. The monotreme has an average body temperature of about 32 °C (90 °F) rather than the 37 °C (99 °F) typical of placental mammals.

Research suggests this has been a gradual adaptation to harsh environmental conditions on the part of the small number of surviving monotreme species rather than a historical characteristic of monotremes.

Like other mammals, monotremes are warm-blooded with a high metabolic rate (though not as high as other mammals); have hair on their bodies; produce milk, through mammary glands, to feed their young; have a single bone in their lower jaw; and have three middle ear bones.

Monotremes were very poorly understood for many years, and to this day some of the 19th century myths that grew up around them endure.

It is still sometimes thought, for example, that the monotremes are "inferior" or quasi-reptilian, and that they are a distant ancestor of the "superior" placental mammals.

It now seems plain that modern monotremes are the survivors of an early branching of the mammal tree; a later branching is thought to have led to the marsupial and placental groups.

Similarly, it is still sometimes said that monotremes have less developed internal temperature control mechanisms than other mammals, but it is now believed that monotremes maintain a constant body temperature in a wide variety of circumstances without difficulty, and are able to adjust their body temperature to suit the surrounding environment.

Scroll to Continue

OK enough you say, lets cut to the chase. Australia's two examples of monotremes could not possibly look more different . They are The Platypus and the Echidna.


The Platypus (Ornithorhynchus anatinus) is a semi-aquatic mammal endemic to eastern Australia.

It is one of the species of monotremes, the only mammals that lay eggs instead of giving birth to live young. It is the sole living representative of its family (Ornithorhynchidae) and genus (Ornithorhynchus). The bizarre appearance of this egg-laying, venomous, duck-billed, beaver-tailed, otter-footed mammal baffled European naturalists when they first encountered it, with some considering it an elaborate fraud. When the Platypus was first discovered by Europeans in 1798, a pelt and sketch were sent back to the United Kingdom by Captain John Hunter, the second Governor of New South Wales. The British scientists were at first convinced that the samples must have been a hoax. Scientists, who produced the first description of the animal in 1799, stated that it was impossible not to entertain doubts as to its genuine nature, and believed it may have been produced by a taxidermist. It was thought that somebody had sewn a duck's beak onto the body of a beaver-like animal. One scientist even took a pair of scissors to the dried skin to check for stitches. The Platypus is one of the few venomous mammals, the male Platypus has a spur on the hind foot that delivers a venom capable of causing severe and lingering pain to humans. It is powerful enough to kill smaller animals such as dogs.

The Iconic Platypus.

The Platypus is the animal emblem of the state of New South Wales,and is featured on the reverse of the Australian 20 cent coin. The Platypus has been used several times as a mascot. "Syd" the Platypus was one of the three mascots chosen for the Sydney 2000 Olympics. "Expo Oz" the Platypus was the mascot for Expo '88, which was held in Brisbane in 1988.

Some interesting history.

Until the early 20th century it was hunted for its fur, but it is now fully protected and it's future is not under any immediate threat. There is no universally agreed upon plural of "platypus" in the English language. Scientists generally use "platypuses" or simply "platypus". Platypus Biology The body and the broad, flat tail of the Platypus are covered with dense brown fur that traps a layer of insulating air to keep the animal warm. The Platypus uses its tail for storage of fat reserves. It has webbed feet and a large, rubbery snout; these are features that appear closer to those of a duck than to those of any known mammal. The webbing is more significant on the front feet and is folded back when walking on land. Unlike a bird's beak (in which the upper and lower parts separate to reveal the mouth), the snout of the Platypus is a sensory organ with the mouth on the underside. The nostrils are located on the dorsal surface of the snout, while the eyes and ears are located in a groove set just back from it; this groove is closed when swimming. Platypuses have been heard to emit a low growl when disturbed and a range of other vocalisations have been reported in captive specimens. Weight varies considerably from 1.5 to 5.3 lb, with males being larger than females: males average 20inches total length while females average 17 inches. The species is endothermic, maintaining its body temperature about 90 °F, lower than most mammals, even while foraging for hours in water below 5 °C (41 °F).


Monotremes are the only mammals known to have a sense of electroreception:- they locate their prey in part by detecting electric fields generated by muscular contractions. The Platypus' electroreception is the most sensitive of any monotreme. The electroreceptors are located in rows in the skin of the bill, while mechanoreceptors (which detect touch) are uniformly distributed across the bill. The Platypuses brain receives input signals from both elecroreceptors and mechanoreceptors indicating a close relationship between the tactile and electrical senses. The Platypus can determine the direction of an electric source, perhaps by comparing differences in signal strength across the sheet of electroreceptors. This would explain the animal's characteristic side-to-side motion of its head while hunting. The convergence of electrosensory and tactile inputs suggests a mechanism for determining the distance of prey items which, when they move, emit both electrical signals and mechanical pressure pulses, which would also allow for computation of distance from the difference in time of arrival of the two signals. The Platypus feeds by digging in the bottom of streams with its bill. The electroreceptors could be used to distinguish animate and inanimate objects in this situation (in which the mechanoreceptors would be continuously stimulated). When disturbed, its prey would generate tiny electrical currents in their muscular contractions which the sensitive electroreceptors of the Platypus could detect. Experiments have shown that the Platypus will even react to an "artificial shrimp" if a small electrical current is passed through it.


In captivity, Platypuses have survived to seventeen years of age and wild specimens have been recaptured at eleven years old. Mortality rates for adults in the wild appear to be low. Natural predators include snakes, water rats, goannas, hawks, owls and eagles. Its habitat includes mainly rivers for both a food supply of prey species and banks where it can dig resting and nesting burrows. It may have a range of up to 4.3 miles, with male's home ranging to accomadate 3 or 4 females.

The Platypus is an excellent swimmer and spends much of its time in the water foraging for food. When swimming it can be distinguished from other Australian mammals by the absence of visible ears. Uniquely among mammals it propels itself when swimming by alternate rowing motion with the front two feet; although all four feet of the Platypus are webbed, the hind feet (which are held against the body) do not assist in propulsion, but are used for steering in combination with the tail. Dives normally last between 30 - 40 seconds, but can last longer although few exceed the estimated aerobic limit of 40 seconds. 10 to 20 seconds are commonly spent in recovery at the surface.

The Platypus is a carnivore: it feeds on worms and insect larvae, freshwater shrimps, and yabbies that it digs out of the riverbed with its snout or catches while swimming. It utilises cheek-pouches to carry prey to the surface where they are eaten. The Platypus needs to eat about 20% of its own weight each day. This requires the Platypus to spend an average of 12 hours each day looking for food. When not in the water, the Platypus lives in a burrow, nearly always in the riverbank not far above water level, and often hidden under a protective tangle of roots.

The Baby Platypuses (Puggles)

Although not official of this writing a strong push is on to call baby monotremes by the name "Puggles", and being such a cute name that's the one I'm sticking with for the moment!

Platypuses exhibit a single breeding season, mating usually occurs between June and October which in Australia is late winter early spring.

After mating, the female constructs a deeper, more elaborate burrow up to 66 ft long and blocked with plugs at intervals (which may act as a safeguard against rising waters or predators, or as a method of regulating humidity and temperature).

The male takes no part in caring for its young, and retreats to its yearlong burrow. The female softens the ground in the burrow with dead, folded, wet leaves and she fills the nest at the end of the tunnel with fallen leaves and reeds for bedding material.

This material is dragged to the nest by tucking it underneath her curled tail. The female Platypus lays one to three small, leathery eggs (similar to those of reptiles), that are about 0.43 in in diameter and slightly rounder than bird eggs. The eggs develop for about 28 days with only about 10 days of external incubation (in contrast to a chicken egg, which spends about 1 day in tract and 21 days externally). After laying her eggs, the female curls around them.

The incubation period is separated into three parts. In the first, the embryo has no functional organs and relies on the yolk sac for sustenance. The yolk is absorbed by the developing young.

During the second, the digits develop, and in the last, the egg tooth appears. The newly hatched young are vulnerable, blind, and hairless, and are fed by the mother's milk.

Although possessing mammary glands, the Platypus lacks teats. Instead, milk is released through pores in the skin. There are grooves on her abdomen that form pools of milk, allowing the young to lap it up. After they hatch, the offspring are suckled for three to four months.

During incubation and weaning, the mother initially only leaves the burrow for short periods to forage. When doing so, she creates a number of thin soil plugs along the length of burrow possibly to protect the young from predators; pushing past these on her return forces water from her fur and allows the burrow to remain dry.

After about five weeks, the mother begins to spend more time away from her young and at around four months the young emerge from the burrow.

The Last Word

The Platypus is sometimes jokingly referred to as proof that God has a sense of humour (at the beginning of the film Dogma, for example). Its unusual appearance has led to its featuring in many media, particularly in its native Australia.

20 Cent Coin

The Platypus on Australia's 20 cent coin.

The Platypus on Australia's 20 cent coin.

Australian 20 Cent Coin

The Platypus has been shown on our currency for example the 20 cent coin.


The Echidna a face only a mother could love

The Echidna a face only a mother could love

The Echidna

Echidnas, also known as spiny anteaters, belong to the family of monotremes.

Together with the Platypus, they are the only surviving members of that order. Although their diet consists largely of ants and termites, they are not actually related to the anteater species.

They live in New Guinea and Australia. The Echidna is named after a monster in ancient Greek mythology.

Echidnas are small mammals that are covered with coarse hair and spines. Superficially they resemble the anteaters of South America, and other spiny mammals like hedgehogs and porcupines. They have snouts which have the functions of both the mouth and nose. Their snouts are elongated and slender. They have very short, strong limbs with large claws and are powerful diggers.

Echidnas have a tiny mouth and a toothless jaw. They feed by tearing open soft logs, anthills and the like, and use their long, sticky tongue which protrudes from their snout to collect their prey. The Short-beaked Echidna's diet consists largely of ants and termites, while the Zaglossus species typically eat worms and insect larvae.

The long-beaked echidnas have tiny spines on their tongues that help capture their meals. Echidnas and the Platypus are the only egg-laying mammals, known as monotremes. The female lays a single soft-shelled, leathery egg twenty-two days after mating and deposits it directly into her pouch. Hatching takes ten days; the young echidna, called a puggle, then sucks milk from the pores of the two milk patches (monotremes have no nipples) and remains in the pouch for forty-five to fifty-five days, at which time it starts to develop spines. The mother digs a nursery burrow and deposits the puggle, returning every five days to suckle it until it is weaned at seven months.

Male echidnas have a four-headed penis, but only two of the heads are used during mating. The other two heads "shut down" and do not grow in size. The heads used are swapped each time the mammal copulates.

The Echinda given the name “Millie” (for Millennium) also represented Australia as a mascot in the 2000 Summer Olympics that were held in Sydney.

The Echidna on a $1 coin

The Echidna on a $1 coin

Echidna on the Australian $1 Coin

The Echidna like the Platypus is associated with the Australian Currency and appears on the $1 (one dollar coin) in all it's glory.

© 2009 Peter


Peter (author) from Australia on October 23, 2020:

Yes Jim I would agree that the Platypus is one of the most oddball creatures on this planet. The scientists are still doing research on the Platypus so it may finish up even more oddball?

Jim Henderson from Hattiesburg, Mississippi on May 21, 2020:

Fascinating creature, the platypus. Certainly seems to be an oddball species with it's own unique 'berth' in the animal kingdom. I'm sure it keeps the taxonomists up at night trying to figure out just 'what' it is.

Thanks. I enjoyed this. After reading, I may be qualified to be a 'platypiologist'!

Peter (author) from Australia on October 15, 2011:

Sorry to disappoint you but the title of the Hub is 'Australian Monotremes' The Platypus is a Monotreme as is the Echidna! I am sure that the platypus needs to know how to catch 'yabbies':-)

Peter (author) from Australia on September 03, 2011:

Well, an ECHIDNA is indeed an Australian Monotreme !

agvulpes999 on September 02, 2011:

heyyyyyy awesome site but what's a echida?

Peter (author) from Australia on August 23, 2010:

The platypus is indeed not a big marsupial and many people including myself are surprised when they see one in real life. I was able to validate the story about the hoax being accurate from a number of various sources as, by it's nature, I do not always rely on Wikepedia being accurate. However in this case I do believe that it and I and the number of other pages you found are indeed true.

We are very lucky here in Australia to have the unique animals such as the Platypus and the Echidna virtually playing on our doorstep.

Thanks for dropping by and telling us your news!

Peter (author) from Australia on June 20, 2010:

blue parrot, you are correct about vulpes being latin for fox. When I joined HP I wanted to get 'silverfox' as a name but it was gone. So 'ag' being the symbol for silver and 'vulpes' being latin for fox. Join the two together and we have silver fox :-)

Thank you for asking and visiting my hub about the Australian monotremes !

blue parrot from Madrid, Spain on June 20, 2010:

But "vulpes" is Latin for "fox", isn't it? Is that a real Latin surname or a nick?

Peter (author) from Australia on April 04, 2010:

Nell Rose, so nice to see you drop in and leave a lovely comment!

Monotreme was also a new word for me I only picked it up doing the research for my Australian Marsupials Hub.

Yes " Puggles " the name for the baby platypus is so cute and I believe that it should be universal :) It almost paints a word picture of the baby?

Nell thanks again for dropping in :-)

Nell Rose from England on April 04, 2010:

Hiya, agvulpes, this was fascinating, I knew a bit about both animals but not that they were called monotreme. I love learning new things like this. And I love 'Puggles' I am going to use it as much as I can lol thanks nell

Peter (author) from Australia on March 11, 2010:

haveezrm, thanks for your visit and fine comment. You were indeed fortunate to see them in the Zoo as in the wild even though they are still around they are very hard to find!

hafeezrm from Pakistan on March 11, 2010:

Thanks for a good hub. I knew about platypus but not monotreme. Thanks for clarifying that platypus is a monotreme. I have been to Taronga Zoo, Sydney and saw plenty of them.

Peter (author) from Australia on February 07, 2010:

Hey Dilda , how is Curl Curl these days ?

Dilda spermus on February 02, 2010:

Balls and titties

Andrew from Italy on January 22, 2010:

Yes, I've heard it. And they are also a good example that in Nature you can't take anything for granted, there are always new things coming to light. Again, a very good hub. :)

Peter (author) from Australia on January 22, 2010:

hypnodude, thanks mate, I appreciate your kind words.

LOL yes God sure does have a sense of humour. When they took a sample back to London they thought it was a rabbit with a Duck's Bill sown on to the body. Go figure!

Andrew from Italy on January 21, 2010:

Great hub agvulpes, very well done. Yesterday I saw the movie Dogma where they say that the Platypus is an example that God has a lot of humor. These animals are very interesting. Rated up and stumbled.

Peter (author) from Australia on December 23, 2009:

GH thanks for dropping by and leaving a comment.

I have not heard of this study can you give me any links to have a look. I would appreciate it thanks :-)

Gener Geminiano from Land of Salt, Philippines on December 23, 2009:

Another great Hub.. there is now a study conducted with these wonderful animals, for these animals has no known immune system yet resistant to almost any forms of ailments... :D

ajcor from NSW. Australia on February 01, 2009:

Glad you and yours are ok....Hope it rains soon - make that soonest - keep safe..cheers

Peter (author) from Australia on February 01, 2009:

G'day annie, thanks for your concern, we were worried Friday with the fire at Endevour Hills, the smoke was blowing right over us. Everything is under control today, it is just muggy. I think that fire in Carrum Downs was near Hall road and Frankston/Dandenong Road. The fires in Gippsland are a worry with thunderstorms expected today.!!!

ajcor from NSW. Australia on February 01, 2009:

You ok with the fires ag? are they near you - i saw Carrum Downs was in a spot of bother and that is where i have family - so if you can sign in for a quick all ok at this end type comment...cheers

Peter (author) from Australia on January 30, 2009:

G'day JamaGenee, I certainly would not have recognised you , very chic!

Yes the echidna does look similar to your porcupine but the porci is classified as a Rodent and they are not related at all. I reckon you would have been a very cute "puggle".

Joanna McKenna from Central Oklahoma on January 29, 2009:

Just *had* to come over and play with your hubs again, so I changed my avatar so you wouldn't know it was me. ;)

This is a great hub, ag!  I nearly wore out a children's book about a duck billed platypus when I was a human "puggle".  (Hope that sticks, btw - too cute!!)  Had no idea the platypus is practically in a class by itself, but the echinda sure looks like our American porcupine.

The Old Firm from Waikato/Bay Of Plenty, New Zealand on January 24, 2009:

Aussie brains don't need any form of surgery surely. Unused and still in the original wrapping - or was that just Sir Les Patterson?

Peter (author) from Australia on January 24, 2009:

TOF Haven't you gone to bed yet. Just between you and me and 6 million Hubbers I'm going to stick to Rubbish Collecting.

Mate. You don't need microsurgery when you operate on an Aussie brain.

I'm sure spryte will forgive you but only when you get it right?

The Old Firm from Waikato/Bay Of Plenty, New Zealand on January 24, 2009:

Better stick with the doctorate, ag, but not in physics, rather a Dag than a Phag. An Australian Brain Surgeon? Has micro-surgery really developed that far?

I picked up the Spryte misspelling on a re-read, but too late to edit. I hope that she forgives me.

Cheers,  TOF

Peter (author) from Australia on January 24, 2009:

G'day SiddSingh,

Thanks for dropping by and leaving a comment. I was very surprised myself when I found out that we had such unique little guys living in our back yard.

I appreciate your kind words.

Peter (author) from Australia on January 24, 2009:

countrywomen, as always it is a pleasure to have you visit my Hubs, especially now that you have bestowed a doctrate upon me!

 So from now on I'll be know as Drag?

Hmmm, a PhD, I was thinking more along the lines of Brain Surgeon.

I feel most honoured to receive one of your "WOW!!'s" and a thumbs up!, I will have to work very hard to maintain the standard. LOL

countrywomen, thank you again for your kind words and support.

Dr.AG ;-[)

Peter (author) from Australia on January 23, 2009: