Animal Hybridization, Signs of Dying Forests

The interbreeding between Niligiri and Hanuman langurs highlights the ecological stress on the Western Ghats, the world’s most fragile biodiversity hotspots.

xVisitors to the Anamalai Tiger Reserve in Tamil Nadu might notice something unusual in the forest canopy. Among the glossy black Nilgiri langurs and the more familiar grey Hanuman langurs, there are animals shaded in brown, gold, and smoky grey — langurs that don’t match the field guides. Researchers say these unusual morphs are likely hybrid individuals, the physical outcome of two species increasingly pushed into a shared and shrinking habitat.

Hybridization among mammals is uncommon. The Western Ghats, one of the world’s biodiversity hotspots, is experiencing a level of ecological stress that is erasing natural boundaries, and l