Everyone knows about the terrestrial kangaroos that hop all over the continent of Australia. Much less well known are tree kangaroos, which have adapted to life in the canopy of rain forests. There are a number of species and subspecies. Most of these live on the second largest island in the world, New Guinea, which lies north of Australia. A couple tree kangaroo species live on the northern tip of Queensland in Australia. Some smaller islands around New Guinea also have tree kangaroo populations.
Tree kangaroos are marsupials, just like ground dwelling kangaroos. Both types have a common ancestor, but tree kangaroos moved from the ground into the trees, filling a niche that monkeys would fill in South America or Africa. They eat mostly leaves, but also consume fruit when it is available. If you think kangaroos might not appear to be well suited to living in trees, one of the first Europeans to see them wrote:
"They move along in short jumps on their hind feet, which do not seem particularly well adapted for climbing trees."
After moving into the canopy, tree kangaroos evolved some adaptations to better survive:
- While ground kangaroos have hind legs that are much longer than their front ones, the legs of tree kangaroos are much closer in length.
- Tree kangaroos have much longer tails, approximately as long as the rest of their bodies. These help them balance when moving around in trees
- The claws on the feet of tree kangaroos are longer and more curved. This helps them grip branches.
Here's a list of tree kangaroo species and sub-species:
- Ursine tree kangaroo
- Grizzled tree kangaroo
- Bennett's tree kangaroo
- Doria's tree kangaroo
- Lumholtz's tree kangaroo
- Matschie's tree kangaroo
- Goodfellow's tree kangaroo
- Buergers' tree kangaroo
- Lowland tree kangaroo
- Seri's tree kangaroo
- Golden-mantled tree kangaroo
Because of the remoteness of New Guinea's jungles, and the presence of cannibals, not many naturalists visited the interior of the island. Therefore there has been very little study. and not much is known about tree kangaroos. Four of these species were not identified until the 1990s. There is no universal agreement among scientists on which are species and which are sub-species.
There is a species called Wondiwoi tree kangaroo that is known from only a single male specimen collected by German ornithologist Ernst Mayr in 1928. He was sent to New Guinea to collect bird skins for the American Museum of Natural History. The Wondiwoi tree kangaroo was found in remote rainforest about one mile in elevation. It is believed to be extinct today, but could still exist.
All tree kangaroo populations are under pressure.from habitat loss and hunting by the native population. The amethystine python is a natural predator of tree kangaroos. Some species are considered critically endangered. There is a Tree Kangaroo Conservation Program in place that is a combined effort by Papua New Guinea and Seattle's Woodland Park Zoo. Tree kangaroos are kept in a number of United States zoos.