Tree nestSun 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.
This bear nest was about 35 m (110 feet) above the ground. If this bear (Batik) was not wearing a radio-collar and I was not constantly tracking her closely in the forest, there was no way that I can figure out that Batik the sun bear was sleeping 100 feet above of me. It took me some time to locate the nest and the saw Batik with my binocular that day due to the dense vegetation and the height of the nest.
I used my Canon S1IS to zoom in to the nest (12 X) and took this photo. Because of the think vegetation and the nesting material, we can barely see Batik’s muzzle and a hind paw hanging mid air.
After waiting patiently for about 3 hours under the tree, Batik finally woke up from her nap and slowly climbed down from the tree. It was really amazing to see how agile a sun bear could be when she climbed down carefully but swiftly from the tree! The dark spot on top of her was the nest she was sleeping ealier.
Another photo of Batik taking her nap. This time she did not construct a proper nest. In stead, she simply slept on branches that could support her body on top of a medium sized tree about 15 m above the ground. Sweet dream!