The word mammalia means of the breast, which is a bit of a misnomer because while kangaroos do produce milk from nipples in their pouches, they don't actually have breasts.
Kata mamalia berarti 'dari payudara.' Nama ini agak kurang tepat karena meskipun kanguru menghasilkan susu dari puting di kantungnya, mereka sebenarnya tak punya payudara.