After approximately ten to twelve days of incubation during which the female curls around the eggs, the young hatch. The newborn young are about 25 mm long, blind and naked. The platypus leaves early in the morning, and hunts by swimming along the bottom of the body of water, attempting to fill its cheeks with captured prey. When the cheek pouches are full, the platypus will surface and chew its food. All echidnas are characterized by a number of distinctive and interesting traits.
All echidnas have barbless spines intermixed with their fur.
Echinda feet are well-evolved for digging, having three to five strong claws. Correspindingly, echidnas are powerful differs, able to dig straight down even from a completely horizontal position. They employ a very effective defense mechansim of simply wedging themselves int a hole or crevise, spines out, and refusing to dislodge. Furthermore, echidnas can withdraw their limbs and stick out their spines, balling up protectively like a hedgehog. The second toe on each hind foot has been specially modified for grooming, cleaning and scratching.