For almost 150 years, the only known samples Jerdon’s tree frog were two specimens housed in the Natural History Museum in London. British Naturalist Thomas Jerdon collected the pair in 1870 in India’s Darjeeling region. Since then, no scientists had come across the frogs, and they were believed to be extinct. But now, according to a new study published in the journal PLOS One, the long-missing species has been found alive in the wild.
A team of researchers led by University of Delhi biologist Sathyabhama Das Biju was surveying the jungles of northeastern India in 2007 when they stumbled across the frogs. According to the Associated Press, Biju and his colleagues weren’t even looking for tree frogs: Their eyes had been glued to the forest floor.
“We heard a full musical orchestra coming from the tree tops. It was magical. Of course we had to investigate,” Biju tells the AP. When they investigated the chorus, Biju and his colleagues discovered that Jerdon’s tree frog (or Frankixalus jerdonii) was not only alive, but could be found throughout the region.
The golf-ball-sized frog is an odd little critter, and not just because it eluded detection for more than a century. The frogs like to breed inside holes and hollows in trees that collect water. When the tadpoles hatch, they drop down into the little ponds until they grow big enough to leave. But while most species of tadpoles only eat plant matter, baby Jerdon’s tree frogs are raised on a steady diet of unfertilized eggs laid by their mother, writes James Owen for National Geographic.
“It’s very clear that they are feeding purely on their mother’s eggs,” Biju tells Owen.
While tadpoles feeding on eggs isn’t unheard of, it’s a very rare trait. Biju and his team noticed that the female frogs have even evolved tube-like genitalia that might help make it easier for them to feed their offspring. At the same time, the tadpoles have evolved smooth mouths that make it easier to eat the eggs, unlike most tadpoles which have tiny proto-teeth to help tear through leaves and other plant matter, James Vincent reports for The Verge.
No one is sure why the frogs went for so long without detection, but it’s likely thanks to a combination of their fondness for treetops and the limited number of scientists that study the region where Biju found the first frogs. However, just because the frogs were recently spotted doesn’t mean they are safe from harm. The forests in northeastern India are particularly vulnerable to logging, and several of the regions where Biju first found the tree frog in 2007 have been razed to make space for farms, the AP reports.
“This frog is facing extreme stress in these areas, and could be pushed to extinction simply from habitat loss,” Biju tells the AP. “We’re lucky in a way to have found it before that happens, but we’re all worried.”