According to a study published on Monday in the journal Nature Ecology and Evolution, the species was last recorded in 1990 when Vietnamese and Russian researchers obtained a specimen killed by a hunter.

Scientists set up cameras for five months in a jungle area near the central coastal city of Nha Trang, resulting in hundreds of photos of the animal.

The mouse deer is among the top 25 most wanted lost species in the Search for Lost Species of the Global Wildlife Conservation (GWC) report. The world's smallest ungulates typically weigh less than 5kg.

According to the GWC, there is very little information about this animal. The re-discovery of the species doesn’t mean it is not threatened, so swift actions are needed for their conservation.