Also known as the ‘Palakkad Gap’, a low mountain pass representing the major break in the Western Ghats mountain range. The Nilgiri Hills rise to around 1100 m AMSL north of the gap and the Anaimalai Hills approximately 2000 m AMSL to the south, with average elevation within the gap 144 m AMSL. The gap has been shown to represent a biogeographic barrier restricting gene flow between populations of numerous species including Indian elephant and various birds.