EVERYDAY SCIENCE

Detailed explanation-1: -Only two kinds of egg-laying mammals are left on the planet today-the duck-billed platypus and the echidna, or spiny anteater. These odd “monotremes” once dominated Australia, until their pouch-bearing cousins, the marsupials, invaded the land down under 71 million to 54 million years ago and swept them away.

Detailed explanation-2: -Ornithorhynchus anatinus, is a unique Australian species. Along with echidnas, platypus are grouped in a separate order of mammals known as monotremes, which are distinguished from all other mammals because they lay eggs. The platypus and echidna have both survived by occupying ecological niches.

Detailed explanation-3: -Eggs and Lactation in Monotremes Monotreme eggs have a leathery shell, like the eggs of reptiles. The eggs are retained inside the mother’s body for at least a couple of weeks. During that time, the mother provides the eggs with nutrients. Platypus females lay their eggs in a burrow.

Detailed explanation-4: -The Nervous Systems of Early Mammals and Their Evolution Monotremes are egg-laying mammals and include the modern platypus and the short-and long-beaked echidnas.