The Platypus (Ornithorhynchus anatinus) is a semi-aquatic mammal endemic to eastern Australia, including Tasmania. Together with the four species of echidna, the platypus it is one of the five existant species of monotremes, the only mammals that lay eggs instead of giving birth to live young.

The calcaneous spur of the platypus

The electrolocation of the platypus

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 Eggs

The latypus lays one to three (usually two) small, leathery eggs (similar to those of reptiles), that are about 11 mm (7/16 inches) in diameter and slightly rounder than bird eggs. The eggs develop in utero 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 platypus curls around them.

The youngs platypus

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.

Alimentation

A platypus must eat large quantities of food to survive - at least half their body weight every day.

The platypus diet consists of insect larvae, snails, yabbies, worms, tadpoles and other fauna and shellfish. They also occasionally eat small frogs, small fish and fish eggs. The platypus sensitive bill detects and uncovers its prey in the mud at the bottom of rivers, around boulders, under logs and among reeds. It snaps up the food, along with grit to aid in grinding, stores it in its cheek pouches, and then comes to the surface to feed. Adult platypuses do not have teeth, instead they have horny plates to crush the food. Young platypuses have molar teeth to chew their food but these are replaced by the horny ridges as they mature.