"We still have a chance to save the species but before we do anything, we have to determine the profile of the remaining group," study leader Peter de Groot said.
Researchers from the Queens and Cornell Universities used genetic tools to determine that only Javan rhino was living in Vietnam in 2009, who was later found dead a year later.
The study confirmed the demise of the Javan rhinoceros population living in Vietnam by analysing animal dung collected with the assistance of special dung detection dogs.
The researchers are now working to save a group of 29 Javan rhinoceroses currently living in a tiny area called Ujon Kolong in Indonesia.
They will use the rhinoceros feces to determine the age, sex and pedigree of this group. This study will provide a direction to try to save the remaining population of one of the most threatened large mammal species in the world.
The research was published in Biological Conservation.