Platypus a strange mammal with a bill and lays eggs.

An image of platypus under water.

When scientists first saw the platypus, they did not know what to make of it.

Here was a living paradox, a pound or two of contradictions that upended some of their scientific beliefs.

We invite you to meet this unique little Australian—a charming, shy, and lovable creature.

First, though, let us go back to the year 1799 and see the ruckus it caused when the very first platypus pelt fell under the gaze of British science.

“He literally could not believe [his eyes],” says an encyclopedia regarding Dr. Shaw, assistant keeper in the Natural History section of the British Museum.

He suspected that “someone had grafted the bill of a duck on to the body of a [four-footed animal].

He tried to [take] off the bill, and today the marks of his scissors can still be seen on the original skin.”

Even when the hide was found to be genuine, scientists were baffled.

The platypus—whose name means “flat-footed”—has a reproductive system much like a bird’s but also has mammary, or milk, glands.

This seeming contradiction raised the question: Did this improbable creature lay eggs, or did it not?

After years of dispute, it was found that the platypus did indeed lay eggs.

But each discovery, it seemed, just added to the puzzle.

How do you classify a creature that:

(1) lays eggs but has mammary glands;

(2) is furred yet has a duck’s bill; and

(3) has a skeleton with the features of a cold-blooded reptile yet is warm-blooded?

In time, scientists agreed that the platypus was a mammal of the order Monotremata.

A monotreme, like a reptile, has one opening, or orifice, for the passage of eggs, sperm, feces, and urine.

The only other living monotreme is the echidna.

The scientific name given the platypus is Ornithorhynchus anatinus, which means “ducklike animal with a bird’s snout.”

Does the small size of the platypus surprise you? 

It does most people.

They imagine a platypus to be about the size of a beaver or an otter.

But as you can see, it is smaller than even the average house cat.

Males vary in length from 18 to 24 inches [45 to 60 cm] and weigh from two to five pounds [1 to 2.5 kg]. 

Females are a little smaller.

Propelled by alternate strokes of its webbed front feet, it quietly dives and remains submerged for one to two minutes as it works its way under the bridge.

Its partially webbed hind feet are not used for propulsion but serve as rudders and work in concert with its tail when it swims.

They also anchor its body firmly when it burrows.

If disturbed, the platypus dives with an audible slap, and that means good-bye! 

So we speak only when it is submerged.

“How does such a little fellow keep warm,” you whisper, “especially in winter’s icy waters?”

The platypus manages well, thanks to two aids: metabolism that produces energy at a fast rate, thus warming it from the inside, and dense fur that keeps the heat in.

That Amazing Bill

The soft, rubbery bill of the platypus is very sophisticated. It bristles with receptors for touch and electrical activity.

At river’s bottom the platypus gently swings its bill from side to side as it scans, detecting even the faint electrical fields created by the muscular contractions of its prey.

While the platypus is submerged, its bill is its main contact with the world, for its eyes, ears, and nose are shut tight.

Watch Those Spurs!

If our little friend is a male, his hind legs are armed with two ankle spurs joined by ducts to two venom glands in the thigh area.

He vigorously thrusts both spurs into an attacker’s flesh in a way somewhat akin to a horseman spurring his mount.

Shortly after the initial shock, the victim suffers severe pain and local swelling.

In captivity, however, the platypus can be as tame as a puppy.

The Healesville Sanctuary, in Victoria, has kept these animals for decades and reports that one early resident would “entertain visitors for hours, rolling over and over to have his tummy scratched . . . 

Thousands of visitors flocked to see this extraordinary little animal.”

Our platypus makes his last dive for the day just as the morning sun peeks over the ranges to our east.

Overnight he has eaten more than one fifth of his weight in food. As he climbs out of the water, the webs on his front feet retract, exposing strong nails.

He now heads for one of his many burrows, which are wisely dug among tree roots for protection against erosion and collapse.

Nesting burrows are normally about 25 feet [8 m] long, but other burrows may be between 3 feet [1 m] and nearly 100 feet [30 m] long and may have many side branches.

Burrows also provide protection from temperature extremes, making them cozy dens for females to raise their young.

Egg-Laying Time

In spring the female goes to a vegetation-lined chamber in one of her deeper burrows and lays from one to three (usually two) thumbnail-size eggs.

She incubates her eggs by enwrapping them with her body and fatty tail.

In about ten days, the babies break free from their parchmentlike shells and feed on the milk served by the mother’s two mammary glands.

The female platypus, by the way, raises her young alone; these mammals give no evidence of long-term pair bonding.

By about February, after a three-and-a-half-month spurt of growth, the young are ready for the water. 

Since a body of water can support only so many animals, the young may eventually search out less populous waters, even crossing hazardous land areas to do so.

In captivity platypuses have lived to over 20 years of age, but in the wild most do not live that long. 

Drought and flood take their toll as does predation by goannas (large monitor lizards), foxes, large birds of prey, and, in far north Queensland, even crocodiles. 

However, man poses the biggest threat to platypuses, not by deliberately killing them (platypuses are now strictly protected), but by relentlessly encroaching on their habitat.

If you ever visit Australia, you can observe for yourself our unique little duck-billed mélange in its natural habitat, as you will not see one in the wild anywhere else in the world.