Tree-kangaroos are marsupials of the genus Dendrolagus, adapted for arboreal locomotion. They inhabit the tropical rainforests of New Guinea and far northeastern Queensland, along with some of the islands in the region. Most tree-kangaroos are considered threatened due to hunting and habitat destruction. They are the only true arboreal macropods.

The Lumholtz's tree-kangaroo is the smallest of all tree-kangaroos. Its body and head length ranges about 48–65 cm, and its tail, 60–74 cm, with males weighing an average of 7.2 kg (16 lb) and females 5.9 kg (13 lb). The length of the Doria's tree-kangaroo is 51–78 cm, with a long 44–66 cm tail, and weighs 6.5–14.5 kg. The Matschie's tree-kangaroo has a body and head length of 81 cm (20 to 32 inches), adult males weigh 9–11 kg (20-25 lb) and adult females weigh 7–9 kg (15-20 lb).

Tree-kangaroos have several adaptations to an arboreal life-style. Compared to terrestrial kangaroos, tree-kangaroos have longer and broader hind feet with longer, curved nails. They also have a sponge-like grip on their paws and soles of their feet. Tree-kangaroos have a much larger and pendulous tail than terrestrial kangaroos, giving them enhanced balance while moving about the trees. Locomotion on the ground is by hopping, as with true kangaroos. Like terrestrial kangaroos, tree-kangaroos do not sweat to cool their bodies, rather, they lick their forearms and allow the moisture to evaporate in an adaptive form of behavioural thermoregulation.

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