The langurs, one of five endemic primate species in Vietnam, used to thrive with thousands in Cat Ba, but their numbers have sharply decreased and now face extinction due to poaching and tourism activities.
Cat Ba langurs dropped by 98 percent within 50 years, from the 2,500 to 2,700 that existed in the 1960s. In the 1990s, when Cat Ba became better known as a tourist spot, poachers hunted Cat Ba langurs.
The number of animals has increased thanks to a conservation project launched in 2000.
A staff member at the Cat Ba National Park, Le Ngoc Nghi, shared that the langurs here were currently strictly protected and tourists rarely see them.
"We monitor and report about the animals daily," Nghi said. "They live in caves and cliffs of 100-150 metres above sea level and go out to search for food, which includes various types of fruits and leaves on large trees and limestone mountains, twice a day at 5 am-9.30 am, and 3 pm-6 pm."
Each troop includes some 10-20 animals headed by a male.
Photographing langurs is challenging, as they live in caves facing the sea and are strictly protected.
The Ha Long Bay - Cat Ba Archipelago has been recognised as a world natural heritage site since September 2023.