Am sure there are more miserable looking animals inside but the sun bear is singled out here in this video and link of an article that I am sharing perhaps because of its rarity.
The sun bear, which is considered the smallest of the bears, can only be found in tropical forest habitats of Southeast Asia, and has been classified as vulnerable by the International Union for Conservation of Nature (IUCN) because of its depleted suitable habitat caused by deforestation.
While it is bad that they are kept in the zoo for public display, it is even worse for their kind because they cannot do what they are suppose to do if they were in the wild, what with their long tongue 20–25 cm (7.9–9.8 in) to extract insects and honey and with their large paws and large sickle-shaped claws, which is believe to be an adaptation for climbing trees.
This video that I am sharing, which was taken by Indonesia-based Scorpion Wildlife Trade Monitoring Group, only shows how inadequate the funding perhaps to make the animals healthy and the facility to remain sustainable.
But what is even worse perhaps is the lack of trained personnel to run the zoo.
What a pitiable sight indeed.
For more on the subject you can also visit this link: http://www.huffingtonpost.com/entry/skeletal-sun-bears-indonesia-zoo_us_58819d50e4b0e3a735684c7f.