Scientists have found a rare glow-in-the-dark shark swimming in deep oceans off Taiwan.
Taiwan's Fisheries Research Institute said five viper sharks, also known as viper dogfish, were found in the Pacific Ocean during a routine survey, reports Newsweek. The shark is distinctive in that it can extend its jaws beyond its mouth.
"The most obvious feature are the needle-shaped teeth, like snake-like fangs; this is also the origin of viper shark name," the institute said, the Daily Mail reports.
Four were already dead, while the fifth died the next day, despite being cared for in 50-degree seawater.
Only a handful of the sharks have been caught since they were first discovered more than three decades ago in 1986 off the coast of Shikoku Island, Japan.
Scientists say the sharks tend to be difficult to find.
"Smaller individuals may escape through mesh nets," Brit Finucci, fisheries biologist, told Earth Touch News. "Or they may inhabit parts of the ocean where there is little human interaction. They're on my wishlist of species to see!"
Marine biologist and shark expert Dave Ebert says it's also likely people have caught the sharks more than it is believed, but confused them for another type of shark.
"I suspect they may be caught a bit more, but unless someone knows what they are or is keenly interested in these 'lost sharks' they usually go unreported," he said.
"It sort of reminds me of a lanternshark that has undergone some kind of diabolical experiment," Ebert added. "It is definitely a bizarre-looking shark!"
As they are so hard to find, scientists know little about the sharks.
In addition to the seas near Japan and Taiwan, the viper sharks were also once spotted near Hawaii. They're believed to migrate from 1,000 to 1,300 feet deep during the day to 500 feet deep at night, and can grow to about 21 inches long.
They feed on crustaceans and bony fishes, including lanternfishes, often extending their fangs out to catch their prey and swallow it whole.
It's not the only unusual animal discovery scientists have made recently.
In New Zealand, a Sydney-led international team of scientists found the fossilized remains of a large extinct burrowing bat that lived millions of years ago, reports Newsweek.
The bat's teeth and bones were roughly three times the size of today's average bat, and it is believed it could walk as well as fly.
According to paleontologist Sue Hand, the bat belongs to a "bat superfamily that once spanned the southern landmasses of Australia, New Zealand, South America and possibly Antarctica" when the four continents were connected as one supercontinent called Gondwana.