Recently, exciting news has emerged from Sanya, Hainan Province: the Asian Small-clawed Otter (Aonyx cinereus), a nationally critically endangered species and Class II State Key Protected species, has been confirmed in the Baolong Forest Farm of Sanya City, greatly expanding the species' known distribution in China.

An Asian Small-clawed Otter captured on camera in Sanya, Hainan Province

This discovery stems from a research project launched by Kadoorie Farm and Botanic Garden (KFBG) and the Haikou Duotan Wetland Research Institute, which found otter signs in Baolong in 2024. Since then, KFBG has continued to strengthen collaboration with the Hainan Wildlife Conservation and Management Bureau of the Forestry Department of Hainan Province, providing tailored biodiversity training for various protected areas and offering sustained technical support to Baolong Forest Farm.

While systematically reviewing the recovered camera-trap data, researchers were delighted to capture footage of the otters and confirm them as the extremely rare Asian Small-clawed Otter. Compared to the more widely distributed Eurasian Otter (Lutra lutra), the Asian Small-clawed Otter is smaller in size, distinguished by their rounded face and partially webbed, reduced claws. In China, it has mainly been found in mountain areas. Though it typically forms pairs or small groups, solitary individuals can also be observed. The rarity of the species, combined with its semi-aquatic and nocturnal lifestyle, poses a significant challenge for field monitoring, and its conservation status is more critical than that of the Eurasian Otter.

Asian Small-clawed Otter status in China:

Historically widespread across Southwest and South China, the Asian Small-clawed Otter has, since 2000, been reported only sporadically in three locations nationwide: Dehong and Xishuangbanna of Yunnan Province, as well as the Diaoluoshan area in Hainan Province. Our targeted surveys conducted with the Diaoluoshan Forestry Bureau between 2016 and 2018 yielded only four independent camera-trap records. All records featured solitary individuals with no evidence of group formation, suggesting the otter population is probably on the verge of local extinction. The discovery in Sanya represents the only confirmed locality outside Diaoluoshan and strongly demonstrates that the lowland forests on the edges of Hainan Rainforest National Park still support rich biodiversity, which must not be overlooked, and highlights Sanya’s vital role in biodiversity conservation as a core city of the Hainan Free Trade Port initiative. As the species is also listed as globally Vulnerable on the IUCN Red List, our findings are essential for updating its global status and informing future research and conservation strategies.

As an apex predator in rivers, the Asian Small-clawed Otter requires abundant crustacean and fish resources, as well as high quality in its habitat environment to thrive, making it also a good indicator species. Hence, their presence provides clear evidence of a healthy, functioning aquatic ecosystem. Looking ahead, there is a continued need to gradually strengthen local habitat protection, mitigate threats and engage local communities to jointly safeguard the long-term survival of this nationally important population.