* Kingdom: Animalia (Animals)
* Phylum: Chordata (Chordates)
* Class: Mammalia (Mammals)
* Order: Monotremata (Monotremes)
* Family: Ornithorhynchidae
* Genus: Ornithorhynchus
* Species: Ornithorhynchus anatinus
Therefore, the platypus is a monotreme. Monotremes are a unique group of mammals that lay eggs, unlike most other mammals who give birth to live young.