- Last updated:
- 20 Feb 2019
When creeks and water holes dry up during prolonged dry spells many creatures, dependent on accessible water, perish. Fish and tadpoles and sometimes small turtles are among them. Others, like several frog species either burrow down into cooler soil or find moist and shaded niches to wait until the rains come.
One of our most iconic wildlife species, the Platypus, cannot wait it out – it needs water to hunt for its food. As a result platypus goes out in search of suitable pools, often ending up in dams and large ponds cut off from protective habitat (and each other). This brings the shy and elusive animals into contact with and under observation by people, although often their presence is betrayed by no more than a swirl in the water.
Fortunately the recent heavy rain set the streams flowing again with platypus taking full advantage to find and utilise ‘revitalised’ habitat. The platypus pictured, despite having a ‘bad hair day’, actually came out of the water to have a good scratch and a look at the camera.
In the 1700 – 1800s there was great interest in Natural Science, particularly in France and England. Naturalists like Joseph Banks joined or mounted expeditions to bring back plant and animal specimens from foreign lands. In 1799, 11 years after the First Fleet arrival, the body of a platypus, preserved in alcohol, arrived in England. At the time there was a lot of “nature- faking” going on so this weird specimen was initially treated as a hoax. What else could it be? It had the body of an otter, the tail of a beaver and the bill of a duck.
Scientists of the time scrambled to examine the creature and competed with one another for access to more pickled specimens arriving from Australia.
This animal had two of the identifying characteristics of mammals – hair and a four- chambered heart (all mammals, including whales and dolphins, have some hair). But it had no visible external mammary glands. The bill only superficially resembled that of a duck and functioned quite differently. Further, some internal organs resembled those of lizards but there were also signs of internal mammaries. Clearly this was not a standard mammal. So what was it? The arguments involved scientists from all over Europe and already the strong creationist lobby thwarted science with religion. The creature was given the name Platypus anatinus (flat-footed duck-like) but the genus name was found to have been given to a beetle even earlier so the name Ornithorhynchus anatinus (birds beak duck-like) was given. But in popular language the name platypus stuck.
A very significant anatomical feature was the presence of only one hole to service the bodily functions of reproduction and excretion. This was already known for the echidna so a new order of animals was erected: the Monotremes (literally “one hole”) the only members of which were the echidna and the platypus.
Yet the major question remained – exactly how did they reproduce? They were not designed to give birth to live young as placental mammals do. Were they oviparous, laying eggs like birds and many reptiles, or perhaps ovoviviparous, producing and hatching eggs inside the mother before the young are expelled (like our Blue- tongue lizards). Whoever solved this question was certain to be acclaimed so more and more specimens were needed. Over the next eighty or so years naturalists were sent out to the colony to get answers and specimens. Hundreds of platypus were shot and speared and the carcasses pickled in alcohol and sent to England for dissection. Attempts at live exports failed. The knowledge of local Aboriginal People were either misunderstood or ignored.
Then in 1884 a young scientist observed a platypus in the process of laying an egg, with another egg already laid. That settled the argument: the platypus is an egg-laying mammal.
We are all familiar with our iconic platypus – it is even engraved on our 20 cent coins.
Its beady little eyes are set high and the nostrils are near the tip of the “bill”, its ears are small slits, not readily visible. The body is covered in dense water-resistant fur and the front feet, used for paddling (the hind legs are not) have webbing extending out past the claws, which are folded in when walking.
Platypus are fairly small, only reaching up to 400 mm head-and-body length, with the flat tail adding another 150mm or so. Their mouth is located under the “bill” which houses electroreceptors picking up impulses from prey items like worms, insect larvae, yabbies etc.
Male platypus have “spurs” on their hind legs containing a venom capable of inflicting severe pain.
Females lay two eggs in deep burrows in stream banks. The eggs hatch in about two weeks and the young are fed by the mother inside the burrow for four to five months. There are no teats; the milk exudes from pores in the skin and is lapped by the young.
Platypus are very secretive and difficult to spot in their aquatic habitat, especially since they are largely nocturnal or crepuscular. Their range is right along the east coast including Tasmania.
In general they are not an endangered species but populations can be severely stressed in periods of drought. If one turns up in a dam or creek on your property, quietly observe but please do not disturb it.
Article by Ken Hepers
Photos by Anne-Marie Dineen