The Platypus – The Poisonous Mammal That Lays Eggs

The Platypus is a semi-aquatic egg-laying mammal found in eastern Australia, including Tasmania. It has unique features among mammals, such as its bill and feet. It’s also one of the few egg-laying mammals, and on top, it has poisonous ankle spurs.
It’s a close relative of echidnas, differing mainly in shorter beak and webbed feet. The mouth looks like that of a duckbill platypus, but it has no teeth on the inside. Instead, it uses horny pads to grind up food.

The average adult platypus weighs about 2 pounds (1kg) and measures 19 inches (48cm). Their body length is usually between 12-15 inches (30-38cm) from head to tail. Females are smaller than males, and their young weigh less when they are born. Platypuses come out only at night or dusk from burrows dug into river banks with strong front claws for protection against predators such as snakes or native dogs.

The bill looks like a duck’s bill, but instead of teeth, it feels like a rubber band.
Platypuses do not have external ear flaps. Instead, their tail is flat and broad, similar to a beaver, which they use for swimming. Like other mammals, the Platypus has teats on its body to nurse its youth after hatching.

The Platypus belongs to the monotreme class. Monotremes are mammals with reptilian characteristics. Like reptiles, they lay hard-shelled eggs in amniotic sacs that keep the embryo warm until it is ready to hatch out of the egg.

The Platypus and two species of echidna (or spiny anteater) are Australia’s only known monotremes—all other mammals are marsupials or placentals (creatures with pouches for carrying their young).

Why is the Platypus a mammal if it lays eggs?

Platypuses are mammals because they produce milk to feed their young and have hair covering most of their bodies. On the other hand, platypuses lay eggs instead of giving live births like reptiles and birds. Like birds, they also have horny egg-tooth ridges on the upper and lower edges of the bill.
The Platypus is an ancient animal whose fossilized remains are about 40 million years old. Based on fossils, scientists think that the present-day platypus’ ancestors were the first mammals that developed from reptiles around 165 million years ago during the Jurassic Period, which would explain why they lay eggs (like reptiles). As with any other living animal, the Platypus has significantly evolved since this time.

The Platypus is the only extant representative of its clade.

Is The Platypus Poisonous?

Platypuses are born with ankle spurs, which have a venom gland on top and crural glands beneath it. Only the male’s back ankles are venomous. Their ankle spur is a modified hind limb differentiated from the foot; unlike echidnas, this spur contains venomous neuro-toxic or neurotoxin (a poison that affects the nervous system) protein that produces severe pain and swelling. The amount of venom injected is enough to kill a small animal but not lethal to humans. However, the pain from the wound will be excruciating and long-lasting and leave a higher sensitivity to pain for several days or weeks.
A platypus’ ankle spurs are used mainly for defense. If stepped on or handled incorrectly, they can deliver an excruciatingly painful wound to humans.

The venomous nature of the Platypus makes it unique among mammals and other vertebrates. Except for the Platypus and its extinct tailed ancestors, only two venomous mammals still exist today: electric eels and cone snails.

Where do they live, and what do they eat?

Platypuses are largely nocturnal (active mainly at night) except when breeding when they become more active during daylight hours in the summer months.
They dig burrows in riverbanks for shelter and protection from land predators like foxes and owls and those in the water like crocodiles and sharks.

The Platypus feeds on crustaceans, mollusks, aquatic insects, small fish, and frogs.
They have no teeth. They use their thick, rubbery lips to grasp insect larvae and small fish when capturing live prey.

When foraging, platypuses use their bill to detect and dig in the mud for prey. The Platypus closes its eyes and ears when hunting, relying on its bill to detect prey instead. How the Platypus locates the prey is a mystery, but it may use electrical impulses or senses when hunting for crustaceans.

The bill of a platypus is covered with sensitive nerves that can detect slight changes in water pressure to find food; and electroreceptors that can sense electrical fields produced by animals. By detecting these impulses, a platypus can locate prey such as crayfish or shrimp buried in mud.
The platypus’ incisor teeth grow continually throughout its life. The flat-bladed shape of their teeth is ideal for holding prey, and the curved shape of their cheek teeth is ideal for crushing it.
In winter, platypuses prefer to live in denser water with a mild temperature, and lots of food sources like freshwater crayfish and shrimp are available. Therefore, they do not hibernate in winter but will reduce their movement and metabolic rate to conserve energy.

They leave the burrow only when necessary to find food or a mate. Females can stay in the burrow for 18 days during the breeding season.

How do they behave as a family?

Platypuses are solitary mammals except when breeding or in female social groups with offspring during summer. Although male platypuses rarely leave their home area, females will travel upstream and downstream to feed.

They have an average lifespan of 10 years in captivity; however, they only live about 3 years old in the wild. Males and females live in separate burrows, but they have a long mating period from March to September or October.

When the Platypus is ready to mate, it searches for a suitable nesting burrow. After choosing its burrow, the platypus blocks off the entrance with mud and after a few days of resting will dig out an underground nest for its eggs.

A platypus’ burrow is about one meter long, with a hidden entrance accessed underwater through bill-digging. The Platypus then creates a nesting spot in the side of the tunnel, where a single egg (sometimes two) is laid and incubated for between three to four weeks until it hatches.
The young Platypus remains in its burrow for three to four months before it ventures out into the world. The male Platypus then drives the mother and any older offspring out of his territory when they become mature enough to breed.

They leave the burrow only when necessary, for example, to find food or a mate. Females can stay in the burrow for up to 18 days during the breeding season, where they’ll birth their babies.
The eyesight of a platypus is good. They also have keen senses of hearing and smell. However, the Platypus has poor eyesight above water so it relies mostly on its electro-receptors in the bill to locate prey. The electroreceptors sense the electrical signals given off by animals on the bottom of rivers and lakes.

How many are left?

It has been estimated that there are about 80,000 platypuses in Australia, mainly in eastern coastal river systems. I guess that makes sense since they are semi-aquatic creatures!

Two extra facts (for those still reading):
The Platypus has several vocalizations, including a grunt that sounds like a raspberry when it is content, and an alarm below that lasts for about two seconds. However, one of the most exciting sounds a platypus makes is a loud hiss when threatened. The source of these noises can be found on their surface, which consists of specialized vibrissae (whiskers).
Platypus meat is a popular food for both indigenous Australians and European settlers. It does not taste like chicken, but those who eat it say it reminds them of duck or goose meat.

In a Nutshell!

The Platypus is a mammal native to eastern Australia and Tasmania and can be found in streams and rivers and artificial ponds such as farm dams.

It’s primarily nocturnal, spending the day sleeping in burrows close to water’s edge or hollow logs on the river bank, emerging after dark to feed mainly on freshwater crayfish (their favorite food) and other small aquatic animals. It’s slightly poisonous, so better not touch it if you see one!