What is the difference between an egg from a bird and a baby from a mammal?

Answer 1

There are three species of mammals that lay eggs: the Platypus and two species of echidna, the long-beaked echidna of New Guinea and the short-beaked echidna of Australia. These mammals, known as monotremes, lay eggs with leathery shells.

Answer 2

Placental mammals and marsupials do not lay eggs. Only monotremes are egg-laying mammals, and these include the platypus and the echidna. These mammals lay soft-shelled, leathery eggs.

Answer 3

Animal's eggs are the same to ostrich eggs because they are all eggs but the only thing is that the ostrich eggs are larger.

Answer 4

Monotremes (egg-laying mammals) lay rubbery-shelled eggs, whilst birds lay eggs with hard shells. Monotreme eggs have larger yolks than birds' eggs.