The primary reason for hunting was to supply the traditional medicine industry. Cat Ba langurs were used to make a "monkey balm" believed to help with erectile dysfunction and other health issues. Since the langurs are so few, hunting takes two to four weeks.
Hunting was primarily done to meet the demand of the traditional medicine sector. Langur monkeys were used to manufacture a remedy known as "monkey balm," which was thought to alleviate issues such as impotence and other health problems. Due to their low numbers, hunting can last anywhere from two to four weeks.