Sun bears in the wild make nest on tree and sleep on these tree nest like orangutans. However, nest building behavior is more common in forest where human disturbance is higher and large terrestrial predators like tigers, and leopards are presence. It makes sense for sun bears to make such tree nest and sleep on high on tree, some as high as 40 meters (128 feet) because it is much safer and dryer on top of tree. These nests usually consist of a pile of tree branches and twigs that are band over from the surrounding centered at a tree fork that close to the main trunk. The diameter of these tree nests ranges from a 1 to 2 meter. Unlike orangutan nest, sun bear rarely snap branches or break branches close by. I still lack of evident that they reuse these tree nests, and believe that they construct new nest every time then need one because wild sun bears tend to wonder a large range, unless there are important food resources available like a fruiting fig tree in the forest. Under this situation, sun bears tend to hang around the area until the food resource is depleted and they have to move on to forage for food. Although the metal baskets that we provide for our captive bears are very different from the natural nest, these bears still love them because these baskets give them a dry, safe, and cozy bed.
Tree nest is one of many ways the sun bears sleep in the wild. I will write more about other ways they sleep or nap in the wild soon!