There are numerous differences.Platypuses are monotremes (egg-laying mammals) but kangaroos are marsupials, meaning they give birth to live young which are raised in a pouch.Platypuses feed on small invertebrates, crustaceans and insect larvae; most kangaroos are herbivores while the smallest species are omnivores.Platypuses dig burrows for shelter, but most kangaroos have no set shelter.Kangaroos have large, strong hind legs and small forepaws, and they move by hopping on their hind legs; platypuses walk close to the ground on four legs, or they swim, extending the retractable webbing between their toes.Female kangaroos have a pouch in the front of their abdomen, with the opening at the top; platypuses have no pouch.There are over 60 species of kangaroos, and just one species of platypus.The male platypus has a venomous spur on each of its ankles. No species of kangaroo has any body part which is venomous.The platypus has a bill with sensitive electroreceptors which can detect even the smallest electrical impulses emitted by the tiny crustaceans and other underwater invertebrates on which it feeds.