Aah, coolest mammal ever. It is a nice mixture of reptiles and mammals, for it belongs to the oldest order of mammals (monotremes) and is more or less a link between those two classes. On the one hand, it lays eggs with a leathery shell and has a cloaca instead of two orifices of the body like other proper mammals, which are typically reptile features (birds have a cloaca too, but nevermind, they are not related to either platypus or you and the other apes). On the other hand, it possesses glands which produce a milk-like liquour for its offspring, but no teats (the milk just kinda “leaks” out and wets the fur) and cares for its little strange platypus-kiddies, which are both features of mammals. Also, platypus is able to more or less have a constant body temperature (another “”I’m a mammal”-sign, though birds also have the ability to do so, but I told you- nevermind).To make the confusion complete: it is one of the around half a dozen mammals which are venomous, but only the ankle spurs of the hind legs of the male animal,and to make it extra special, Nature gave it ten sex chromosomes instead of two and a nice beak.