Ringtail possums are found in Australia and New Guinea, as well as nearby islands. They have been introduced to New Zeeland, where they are considered a pest. They mostly eat leaves, but will also eat fruit, flowers, and the occasional insect or spider. In order to extract as much nutritional content as possible, they will eat their own feces on the food's first pass through, and only discard the twice-digested food on the second pass. Ringtail possums spend most of their time in trees, where they are agile climbers, helped by opposable grasping digits on all four feet and a prehensile tail. The tail is usually held curled into a ring shape when at rest, hence the common name. Although they can be fast and graceful climbers and jumpers, their usual mode of locomotion is slow and deliberate, rarely letting go of one branch until they have grasped another. On the ground they have a clumsy, waddling gait. If disturbed, their usual reaction is to freeze and stare. They often nest together in small groups. There are many different species, the more well known of which are described below.