Monotreme - online puzzles

Monotremes are one of the three main groups of living mammals, along with placentals (Eutheria) and marsupials (Metatheria). The monotremes are typified by laying eggs rather than bearing live young, and by structural differences in their brains, jaws, digestive and reproductive tracts, and other body parts compared to the more common mammalian types. However, like all mammals, the female monotremes nurse their young with milk.

Monotremes are traditionally referred to as the mammalian subclass Prototheria. The only surviving examples of monotremes are all indigenous to Australia and New Guinea although there is evidence that they were once more widespread including some extinct species in South America. The existing monotreme species are the platypus and four species of echidnas. There is currently some debate regarding monotreme taxonomy.

The word monotreme comes from the Greek μονός, monos ("single") and τρῆμα, trema ("hole"), referring to the cloaca.