TedEd: The fish that walk on land

A TedEd by Noah R. Bressman

A walking catfish can jump out of the water if it wants to go somewhere new. Of course, many dangers come with this. Death by dehydration, physical dangers, and predators are all in the mix. This may seem odd, but there are actually hundreds of species of fish that are amphibious or can live on land and in the water. Some types only do this when necessary, while it is a part of life for others. Some fish come out of the water when it is too hot and stay moist in the shade. The walking catfish comes out to eat bugs, and California grunion comes ashore to mate. Normally, fish use gills to breathe, which are feathery organs filled with blood vessels that absorb the oxygen in the water. However, the gills collapse when outside the water. So, some fish have oxygen-absorbing parts inside their bodies or actual lungs. Fish also have thin skin that nutrients can pass through, which makes them dry up outside water. So, some fish flop around in the mud, while others coat themselves in mucus and go deep into the earth. The fins of amphibious fish are extra-strong, enabling them to move around on land. But how do they navigate? Some fish look for reflective surfaces, while others move downward in hopes that water will be downhill. More sophisticated animals like the walking catfish have a lot of taste buds on their whiskers, which it uses to detect prey, water, and harmful areas. So while amphibious fish may have a hard time out of the water, they have evolved ways to solve this over time to become the amazing creatures they are today.

Side note: This actually ties into what I am learning at school, evolution and natural selection.