Scientists Thought This Fanged, Cat-Sized Deer Was Gone for Good—Now It’s Been Found Again in Vietnam

The so-called Vietnamese mouse-deer is an odd-looking creature. The cat-sized critter has a half-silver and half-auburn coat, beady eyes, spindly legs, and a pointed face that does indeed look like a cross between a mouse and a deer—but with fangs. Yes, the mouse-deer is a bit of a weirdo, but that’s not why biologists were shocked to see one on a trail camera.

The Vietnamese mouse-deer—technically called a silver-backed chevrotain (Tragulus versicolor)—has been lost to science for years. No Western biologist had seen one—dead or alive—for more than 30 years. (Researchers obtained dead silver-backed chevrotains in 1990. It was first described by scientists in 1907.) Scientists were concerned that due to poaching, wire snares, and habitat destruction, the creature had vanished from the face of the earth, reports Katherine J. Wu for Nova.

In 2008, the nonprofit group Global Wildlife Conservation (GWC) launched a campaign called the Search for Lost Species with the mission to scour the world for 1,200 species that are lost to science, meaning the animals haven't been photographed, documented or studied for many years and are "feared possibly extinct." Of those, GWC has a 25 “most wanted” species list that included the silver-backed chevrotain.

To find the elusive mammal, GWC biologists An Nguyen and Andrew Tilker set out for a forest near the southern beach city of Nha Tran. It was there, back in 1907, that the mini-creature was last spotted by scientists. But just because the creature fell off the radar of research doesn’t mean it was ever lost to locals.

The team talked to local hunters and government forest rangers about whether they had seen any of the Vietnam mouse-deer’s trademark silver rumps, which set the deer apart from similar species, like the lesser chevrotain (Tragulus kanchil). The scientists were then guided into parts of the forest where the mammals may have been spotted. Then the team set up cameras and waited. After five months, the team collected 275 photos of the species.

“I was overjoyed when we checked the camera traps and saw photographs of a chevrotain with silver flanks,” says Nguyen in a statement about the discovery.

The team then set up another 29 cameras in the same area; this time collecting 1,881 photographs of the chevrotain over the course of an additional five months. This week, they published their findings in the journal Nature Ecology & Evolution.

So, the silver-backed chevrotain was never really lost after all. Even still, documenting and tracking species is an important practice during a period of unprecedented species loss.

“We should think that we’re still pretty damn lucky that this species is still around,” as Liana Zanette, a conservation biologist at Western University in Canada who wasn’t involved in the study, tells Nova’s Wu. “We’ve been given another opportunity to try and preserve it, and that’s where the focus needs to be now.”

The team did not reveal the specific coordinates of their GPS cameras or the location where the population was spotted in order to protect them from hunting, reports Bill Chappell at NPR. This practice is becoming more common among scientists because poachers have started turning to scientific papers to locate their targets.

While the Vietnam mouse-deer isn’t the first species to be checked off the Search for Lost Species list, it is the first mammal to be re-discovered. Other lost-and-found species include a golden salamander in Guatemala, a flesh-eating pitcher plant located in the Canadian wild, and what is believed to be the world’s largest bee species, which was spotted in Indonesia.

GWC’s scientists are still on the hunt for many other “missing” creatures, including the lesser pygmy flying squirrel, the flightless scaly-tailed squirrel, and the Tasmanian tiger and much more.