Our fish-like ancestors likely acted this way when transitioning from water to land.
A species of cave fish has been documented ‘walking’ up waterfalls like a lizard. It is a discovery that could have important implications for understanding evolution.
A team of researchers from the New Jersey Institute of Technology (NJIT) traveled to Thailand to study Cryptotora thamolica, a species of blind fish found in just a small number of caves. In fact, only 2,000 of the fish currently exist in the wild.
This is not the only species of fish that use their fins to ‘walk’ — several other types of fish walk along the seabed in a hopping motion. However, Cryptotora thamolica is very unique. It climbs up steep rock faces covered by fast-moving waterfalls using its fins, similar to a salamander.
The fish moves by twisting its body from side-to-side and using its front and near fins to take steps up the face of the waterfall. To the untrained eye, it looks more like a lizard than a fish according to The Independent.
The details of the study, published in the journal Nature Scientific Reports, includes the findings of a CT scan of a specimen.
Brooke Flammang from NJIT explains in a YouTube video that, of the 30,000 species of known fish to exist, she has never come across a creature like this in her entire career.
“From an evolutionary perspective, this is a huge finding. This is one of the first fish that we have which is a living species, which acts in a way we think fish must have acted when they evolved from a fluid environment to a terrestrial environment at the very beginning of the fin-to-limb transition, when the first limbs evolved in our earliest ancestors.”
This cave fish offers biologists a look into what life may have been like 400 million years ago — when aquatic creatures began transitioning to walk on land. However, since the fish are so rare, it is difficult to study them.
Not only that, the species lacks eyes, which also raises some questions.
“How do they find each other and make babies? How do they sense where their food is?” asked Flammang in the video. “All of these are interesting and important questions.”