Email Print Share
September 24, 2020

Study suggests at least 11 fish species are capable of walking

An international team of scientists has identified at least 11 species of fish suspected to have land-walking abilities. The findings are based on CT scans and a new evolutionary map of the hillstream loach family, which includes the only living fish species caught in the act of walking: a rare, blind cavefish known as Cryptotora thamicola, or the cave angel fish. Pinpointing which species of hillstream loaches have walking capabilities can help scientists piece together how the first land-walking vertebrates might have come to be. The research was funded in part by the U.S. National Science Foundation.

Credit: National Science Foundation/Karson Productions

Fish out of water.

I'm Bob Karson with the Discovery Files, from the National Science Foundation.

Ever imagine the first ancient underwater creatures that emerged and walked on land? (Sound effect: cartoon fish voice) "Ok, I'm swimming, climbing, pulling, dragging, walking. Walking? (Sound effect: car horns) Hey I'm walkin' here!"

The quest to piece together that epic evolutionary step when land-walking vertebrates first appeared, is getting some help from U.S. and Thai scientists who’ve identified at least 11 species of fish suspected to have or have had land-walking abilities. (Sound effect: cave sounds) (Sound effect: reverb) Right now, there is only one living species of fish that's been observed walking: a Loach called the Cave Angel Fish -- a rare, blind cave-stream-dweller whose pelvis more closely resembles an amphibian's. An adaptation that lets it grip rocky streambeds, even climb waterfalls.

The team used CT scans to study the bone structure of some 30 Loach species. The eleven that were good candidates for walking all had an unusually hefty pelvic girdle and, unlike most fish, bone that connects the spine to the pelvic fin. With DNA analysis, the team used hundreds of genes to trace how pelvic shapes in these fish evolved over time.

A greatly improved understanding of the evolution of an extremely uncommon event -- (Sound effect: cartoon fish) "heads up -- comin through!" -- the ability of a fish to walk on land. (Sound effect: cartoon fish) "Anybody see my step counter?"

"The discovery files" covers projects funded by the government's National Science Foundation. Federally sponsored research -- brought to you, by you! Learn more at or on our podcast.

Images and other media in the National Science Foundation Multimedia Gallery are available for use in print and electronic material by NSF employees, members of the media, university staff, teachers and the general public. All media in the gallery are intended for personal, educational and nonprofit/non-commercial use only.

Images credited to the National Science Foundation, a federal agency, are in the public domain. The images were created by employees of the United States Government as part of their official duties or prepared by contractors as "works for hire" for NSF. You may freely use NSF-credited images and, at your discretion, credit NSF with a "Courtesy: National Science Foundation" notation.

Additional information about general usage can be found in Conditions.