Each year or so, the short-beaked echidna (Tachyglossus aculeatus) lays one leathery egg “about the size of a grape,” says Christine Cooper of Curtin University in Perth. The puggle, as a baby echidna is called, hitchhikes for weeks as mom forages. Echidnas’ toes point backward on their hind paws but forward on the front, and their short legs slant outward in a bit of a reptile sprawl, says Christofer Clemente of University of the Sunshine Coast in Sippy Downs, Australia.