A tiger’s roar might be as unique as a human’s voice. Researchers from nonprofit conservation group the Prusten Project are attempting to distinguish individual tigers from each other in order to keep track of them aurally. 

An initial study of captive Bengal tigers in a U.S. sanctuary showed that individual tigers have voices that vary in their frequency and length, allowing researchers to pick them out of a crowd. And since female tigers generally roar at much higher frequencies, the researchers were able to distinguish their roars from males’ with 93 percent accuracy. (The study has yet to be published.)

Being able to identify tigers by their roars could allow for remote population monitoring, meaning researchers could take stock of endangered tigers hidden in the thick jungle without having to visually spot them. A similar project is in the works to study elephant populations.  

The Prusten Project launched acoustic tiger monitoring efforts in Sumatra earlier this year, and they are also testing the technique in Thailand. 

[h/t: Popular Science]