Summary:
- Monotremes are mammals that reproduce by laying eggs.
- The only living monotreme species are the platypus and echidnas.
- Platypus females lay their eggs in a burrow.
- Echidna females have a pouch in which they store their eggs.
- Monotreme reproduction is the least risky for the mother.
- However, eggs are harder to protect than is an embryo or a fetus in a pouch or uterus.
- The mother doesn’t need to eat more or put herself at risk by carrying and delivering a fetus.