May 08, 2015 I Paul Seaburn

Wall-Climbing Catfish Has Evolution Experts Climbing Walls

Scientists exploring a cave in Ecuador were shocked when a catfish crawled out of an underground stream and climbed 10 feet up a wall. Did they witness evolution at work? Is this a sign of the Apocalypse? Are the fish coming after sushi eaters?

According to the April 16 edition of the journal Subterranean Biology, naturalist and speleologist Geoff Hoese was leading a team exploring limestone caves near Tena, Ecuador, when they observed a number of small catfish climb a nearly-vertical wall, with some reaching a height of three meters before splashing back into the water. Fortunately, some team members had cameras to record the amazing never-before-seen climbers.

The catfish are members of the suckermouth armored catfish family (Chaetostoma microps) which, until now, have only been found above-ground in the Amazon River. There they use their sucker mouths to attach to rocks and trees to avoid being washed downstream by the rapid waters.

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Sucker-side-up view of the wall-climbing catfish

The cave catfish have gone a step further and use their mouths to climb walls that are covered with a film of water trickling from small underground streams. They can do this because they have something more than their upstairs relatives, says Hoese.

(They have) a number of modified structural elements of their fins, skin, and mouths.

The only other known wall-climbing cave fish is the loach from Thailand (Cryptotora thamicola) which needs more water in order to get up less steep inclines.

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A close-up view of a wall-climber in action

Did these catfish climb out of the water in order to survive life in the cave? Hoese’s answer is vague.

There isn't enough data at this point to do more than speculate, but it's nice to think that we may be watching a small but significant evolutionary step as a species moves from one niche to another.

Will this discovery change the study of evolution? Will it change the way seafood is served?

What would Darwin say?

Paul Seaburn

Paul Seaburn is the editor at Mysterious Universe and its most prolific writer. He’s written for TV shows such as "The Tonight Show", "Politically Incorrect" and an award-winning children’s program. He's been published in “The New York Times" and "Huffington Post” and has co-authored numerous collections of trivia, puzzles and humor. His “What in the World!” podcast is a fun look at the latest weird and paranormal news, strange sports stories and odd trivia. Paul likes to add a bit of humor to each MU post he crafts. After all, the mysterious doesn't always have to be serious.

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