Monotreme Animals What is a Monotreme Mammal?

Description of Monotreme Animals What Mammals Lay Eggs?


A monotreme is a primitive type of mammal that lays eggs like a bird or reptile but feeds its babies milk like a mammal. Monotreme means "one hole". This is because these animals have only opening for their anus, urinary and reproductive tracts – cloaca. This is similar to birds and reptiles. Monotremes are the only egg laying mammals in the world. The platypus and echidna are monotremes.

Monotremes are warm blooded but have a slightly lower metabolic and heart rate than other mammals. This means they need less energy than equivalent sized mammals. Monotremes have fur but no teeth.

Monotreme (mo-no-tree-m) pronunciation.


The female lays a single leathery-egg directly into a shallow pouch in her belly. When the minuscular little baby animal hatches, usually in about ten days,


The babies lick milk that seeps out of pores in its mother's abdomen.

Body Temperature

Monotremes have the lowest body temperature amongst mammals at 30°C. This 8°C lower than a placental mammal and 5°C lower than a marsupial.


Monotremes have basal metabolic rates (BMRs) 25-30% lower than those of most placental mammals.

Related Article: Echidna — A Living Relic from Early Mammals

Related Article: Platypus — Duck-billed Platypus

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