Asir Jawahar Thomas Johnsingh (14 October 1945 – 7 June 2024) was an Indian vertebrate ecologist from Tamil Nadu.

[2] Johnsingh was born in Nanguneri,[3] in Tirunelveli District of Tamil Nadu in 1945, and spent his early years there.

[4] His research during 1976-78 focused on the ecology and prey-predator relationships of dhole, other carnivores and ungulates in Bandipur National Park.

[5] After brief stints as a professor at Ayya Nadar Janaki Ammal College, Sivakasi, and as a postdoctoral fellow at the Smithsonian Institution in Washington, D.C., he returned to India in 1981 to work with the Bombay Natural History Society.

In 1985, he joined the newly-established Wildlife Institute of India, Dehradun, where he became the head of the faculty of wildilfe sciences, and retired as the Dean in 2005.