Endemic to the forests of south and southeast Asia, the silver-backed chevrotain, or Vietnamese mouse-deer, is one of the world's most elusive animals. The rabbit-sized critter is only known to science through five specimens, four of which were recorded by researchers in 1910. The fifth was killed by a hunter and donated to scientists in 1990. Since then, there have been no recorded sightings of the animals, leading many to fear they had gone extinct. Now, thanks to the efforts and persistence of a team led by biologist Andrew Tilker, the species has not only been rediscovered but also photographed in the wild for the first time!
"It's a really cool species, and we'd long hoped to find the proof they were still around," says Tilker, a doctoral student with the Leibniz Institute for Zoo and Wildlife Research in Germany.
The animal, which looks like a hybrid between a mouse and a deer, is the smallest member of the hoofed ungulate family, which includes deer, giraffes, sheep, llamas, and many others. They live alone, or in pairs, and have a distinguishing silver sheen on their rumps, along with tusk-like incisors. Because chevrotains lack horns and antlers, and the teeth are unusually long in males, scientists believe the "fangs" are used to compete for territory and mates.
Tilker and An Nguyen, a biologist and Ph.D. student with the Leibniz Institute for Zoo and Wildlife Research, began their search by talking to the local residents and rangers familiar with the dense forests. They then set up camera traps in three different Vietnamese provinces where there had been recent mouse-deer sightings. To their surprise and delight, over the course of two six-month study periods in 2017 and 2018, the motion-triggered cameras captured 200 images of the animals at 15 different locations.
"The species has been known to local people all along," says Tilker. "In this respect, the silver-backed chevrotain was a species that was 'lost to science,' but it was not lost to local people living in and around its habitat."
The researchers, who published their findings in the journal Nature Ecology & Evolution on November 11, 2019, believe that poaching and habitat loss are the biggest risks to the mouse-deer's existence. They are suggesting additional research to find more specimens. "It is important that scientists conduct follow-up surveys to search for additional populations, assess how common or rare the species is in places where it occurs, and to assess the major threats that it faces," says Tilker. "The involvement of local people will be critical in all of these efforts."
The mouse-deer is the first creature found through the Search for Lost Species, a Global Wildlife Conservation initiative to find and protect around 1,200 breeds of animals and plants that have been lost to science. However, they are not unique in their status as a rediscovered species. Recently, scientists have also found specimens of other "vanished" animals, including Wallace’s giant bee, the Lord Howe Island stick insect, and the Varanus douarrha monitor lizard. Hopefully, they will be able to find all the others as well. As Tilker succinctly puts it, "We shouldn't give up on them just because we haven't seen them in a long time."
Resources: Natgeo.com, CNN.com, NewsAtlas.com