Goodfellow's tree kangaroos are primarily solitary (2), with large male territories overlapping several smaller female territories (5), and breeding occurs year-round (2) (6). As a marsupial, the female of this species has a well-developed pouch on its abdomen into which the tiny newborn climbs, where it grows for up to the next ten to twelve months. Even after it leaves the pouch, the joey continues to return to nurse for several months (3). Sexual maturity is reached at two years of age, and individuals have been known to live over 14 years in captivity (5). A superb climber and capable of leaping long distances, this tree kangaroo spends much of its time in the trees, but also frequently descends to the ground in search of food (6). A largely nocturnal species, Goodfellow's tree kangaroo emerges at night to feed mainly on leaves and fruit, but also on flowers, grass and even cereals along the forest edges. Its large, sacculated stomach is specially adapted to this diet, allowing the breakdown and digestion of tough leafy material (3).