Possums are quadrupedal diprotodont marsupials with long thick tails. The smallest possum, indeed the smallest diprotodont marsupial, is the Tasmanian pygmy possum, with an adult head-body length of 70 mm (2 3/4 in.) and a weight of 10 g (3/8 oz.). The largest is the bear cuscus that may exceed 7 kg (15lb. 6oz.). Possums are typically nocturnal and at least partially arboreal. The various species inhabit most vegetated habitats, and several species have adjusted well to urban settings.