Researchers at the Marine Biological Laboratory (MBL) in Woods Hole, Massachusetts, are studying why a fish called Polypterus can walk on land. They think that walking underwater may have been the first step in the evolution of walking on land. They are using a tank with a treadmill to measure how Polypterus moves and how much energy it uses. They hope to understand how and why walking began in vertebrates.

The first animals to take to the land from the seas were tetrapods, or four legged fish who struggled to survive on land. Some fishapods, such as Qikiqtania just gave up, took a U-turn and returned to the oceans, while others struggled to evolve for life on land because of a limited number of bones. These early tetrapods could not have learned to walk directly on land, and required strong fins to even support their weight in the absence of water. Scientists believe that the evolutionary origin of walking traces back to a time before the tetrapods made the transition from water to land.

For a fish, swimming in the water can be compared to riding a bike. It consumes a lot of energy to swim very, very slowly. At lower speeds, fish are just unstable in the water. Scientists believe this is the reason that some fish began to walk on the seafloors. Researchers are investigating these theories, using an underwater track, a treadmill, high speed cameras, and Polypterus, a fish that thinks that it is a salamander. Read the full story at

Source: Scientists Investigate the Origin of Walking by Placing Fish on a Treadmill | NewsNine