Public domain image from Webster's Dictionary 1911 larger image
It is similar to the beaver with a brown furry body and tail, but has webbed feet and a soft, rubbery snout that resembles the wide bill of a duck. Because of this it is frequently (and erroneously) called the duckbill platypus. The normal weight of the platypus is in the range of approximately 2 to 6 pounds (1 to 3 kilograms).
The platypus is a monotreme, one of the few mammals that lay eggs and hatch them instead of giving birth to live young. Its species name is Ornithorhynchus anatinus. The Latin name ornithorhynchus literally means "bird nose". (The common name "platypus" was originally given to it as a Linnean species name, but was discovered to already belong to an obscure invertebrate.)
The platypus is a semi-aquatic animal, inhabiting small streams and rivers. It is an excellent swimmer and spends much of its time in the water. It keeps its eyes tightly shut when swimming, relying completely on its other senses. All four feet of the platypus are webbed. When it swims, it propels itself by paddling with the front two feet. The tail and hind feet assist in steering but not propulsion.
The platypus is a carnivore. It feeds on worms and insect larvae that it digs out of the river bed with its snout. Its bill is very sensitive, allowing it to hunt its food without use of eyesight. The platypus is the only mammal possessing the sense of electroception: it locates its prey in part by detecting their body electricity.
The male platypus has venomous spurs on its ankles. The poison is not lethal to humans but does produce pain and swelling.
The platypus digs long tunnels in the river banks to nest. It fills its nest at the end of the tunnel with reeds for bedding material. When the female is ready to give birth, she blocks off the tunnel for protection.
As a monotreme, the platypus does not give birth to live young but instead lays eggs in its nest. When the eggs hatch, the small babies emerge and cling to the mother. Like other mammals, the mother produces milk for thenew babies. The platypus does not have apparent external nipples, but excretes the milk through small openings in the skin.
When the platypus was first discovered by Europeans in the late 1800s, a pelt was sent back to Britain for examination by the scientific community. The British scientists were at first convinced that the seemingly-odd collection of physical attributes must be a hoax.