Life on The Karst

Life on the Karst is a project documenting some of the incredible biodiversity of the South China Karst system. This vast landscape, which traverses four southwestern Chinese provinces, was inscribed as a UNESCO World Heritage Site in 2007. It covers a total area of more than 97,000 hectares and is home to an astonishing array of unique and endangered wildlife. Still, to this day, deep within the realms of uncharted sinkholes and on the pinnacles of limestone monoliths, new species are being identified.

Part 1 // Elves of The Rock: The White-headed Langurs of the Viet-China Border

Oriental Garden Lizard Calotes versicolor (widespread), or subspecies Wang's Garden Lizard Calotes wangi (limited to Vietnam-China border region, identified in late 2023) munching on a bemused Mantis. Guanxi Province, China.

Part 1

Elves of the Rock: The White-headed Langur's of the Viet-China Border

This individual has an interesting case of Sectoral Heterochromia. This means the Iris of one eye has a section of a different colour. In Humans, Heterochromia iridium, the umbrella term for each variety of the phenomenon, is present in just 1% of the population. Sectoral is even rarer, and occurs in a small portion of that 1%. In non-human primates, due to considerably less phenotypical variation in eye colour, coupled with the rarity of eye colour variety, in the first place, in most NHP's, the condition is incredibly rare. What makes the condition more likely is the presence of inbreeding, and the potential of physical trauma to the eye. Of course, in such an isolated population, inbreeding can become a real problem, and injury is not uncommon. However, despite not knowing for certain the exact likelihood of observing a White-headed Langur with Sectoral Heterochromia, I can confidently say that this encounter was a surprise and a delight!