Egg-Laying Mammals

This small mammal order includes just three species, all found in Australia and New Guinea. These unusual animals are all that remains of a group of mammals that diverged, in evolutionary terms, from the rest of the class around 200 million years ago. The lines of the three surviving species have persisted, relatively unchanged, for tens of millions of years since, due to highly specialized lifestyles. The two echidna, or spiny anteater, species use a jaw elongated into a sensitive beak-like probe that seeks our food among soil and leaf litter, while the semi-aquatic platypus finds food with a duckbill that detects electrical activity of its crayfish prey. All species (But only the male platypus) are equipped with with a venomous spur on the back leg, used in fight over mates and in defence.