

Average basal metabolic rate 468 cm3.O2/g/hr.( Grant and Temple-Smith, 1998 Pasitschniak-Arts and Marinelli, 1998) There is a significant reduction in body fat after winter for both young and adults (Pasitschniak-Arts and Marinelli, 1998). The young are smaller than adults in size. The young have milk teeth while the adults have grinding plates.

Females have mammary glands but no nipples. Males are generally larger than females, and have two venom glands attached to spurs on their hind legs. Each foot contains five digits each consisting of a broad nail for the forefeet and sharp claws for the hind feet. They have short limbs, naked soles, webbed forefeet and partially-webbed hind feet. Two nostrils are located on top of their bills and their eyes and ears are on either side of their heads. They have bills that closely resemble those of ducks, and flat and broad tails resembling those of beavers (Grant and Temple-Smith, 1998). Duck-billed platypuses are stream-lined and elongated, they have fur ranging from medium brown to dark brown on the dorsal side and brown to silver-gray on the ventral side. They have a cloaca through which eggs are laid and both liquid and solid waste is eliminated. These species are unique among mammals in that they retain the ancestral characteristic of egg laying.

