How Fish Evolved to Climb Waterfalls With Their Mouths
When it comes to climbing waterfalls, the Nopili rock-climbing goby really puts its teeth into it. The inch-long fish uses suckers in its mouth and belly to move up steep cliffs in its rugged Hawaiian habitat. Because its freshwater habitat is easily disturbed—by a big storm, for instance—the fish often crawl up waterfalls to return upstream.
But how this odd creature evolved to trek vertical distances of up to a hundred feet —the energetic equivalent of a person running a marathon—was unknown, said Richard Blob, an evolutionary biologist at Clemson University. Now, a new paper by Blob and colleagues in the journal PLOS ONE shows that the fish uses the same movements to climb as it does to eat algae.