High atop the limestone cliffs of southern China, the endangered white-headed langur clings to survival. But thanks to an unexpected ally—the langurs’ own droppings—scientists are finding new ways to protect this rare primate.
Researchers at the Guangxi Chongzuo White-Headed Langur National Nature Reserve scour the mountains daily, collecting monkey feces that hold vital clues about the langurs’ health. The yellowish-brown stains on the cliffs, caused by corrosive substances in their droppings, guide scientists to these precious samples. What many dismiss as waste has become an irreplaceable conservation tool.
By sequencing the genes found in the feces, scientists can analyze the composition of the langurs’ gut microbiota. This helps them understand how environmental factors affect the langurs’ health and well-being.
Moreover, measuring cortisol hormone levels in the droppings allows researchers to assess whether the langurs are experiencing long-term stress. “Human activities may impact the living environment of white-headed langurs, potentially causing elevated levels of cortisol in their bodies, which leads to chronic stress,” explains Zhou Chunfang from the College of Life Sciences at Guangxi Normal University.
Chronic stress can lead to behaviors like excessive scratching, increasing the risk of infections from bacteria and parasites. By monitoring stress levels, scientists can recommend creating buffer zones in tourist areas to reduce human impact on the langurs’ habitat.
These science-led conservation efforts are paying off. Once critically endangered with just 300 individuals in the 1980s, the white-headed langur population has rebounded to over 1,400 today. What was once considered waste is now a cornerstone in the fight to save one of the world’s rarest monkeys.
