Platypus and echidnas are classified as monotremes; monotremes have lower body temperatures than other mammals and have short legs which extend out. These features, together with their egg-laying, are more like that of a lizard than a mammal.
Platypus
Scientific name - Ornithorhynchus anatinus
The platypus was thought to be a joke by the first scienists to examine their body in 1799. They are one of the only egg-laying, semi-aquatic mammals in the world. They have webbed feet, a broad tail like a beaver and a characteristic duck-like bill. Closing their eyes and ears when they dive underwater, like a dolphin, electrolocation through their bill is used to find food. This means sometimes they end up on the end of fishing lines, unable to see the danger.
Echidna
Scientific name - Tachyglossus aculeatus
Echidnas feast on ants and termintes and protect themselves with spines, which can reach 5cm long. Solitary for most of the year, until mating time when several males may follow a single female. Taking shelter in rotten logs, stumps, burrows, or under bushes, echidnas go into to a type of hibernation over winter. Surprisingly, echidnas are good swimmers, paddling about with only their snout and a few spines showing above the water. They have even been known to swim amongst the waves in the ocean!
Where can you see both of them?