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| Locomotion of the Lamprey |
| The sea lamprey has two dorsal fins, but lacks pectoral fins and other advances used by modern fish for swimming. The sea lamprey is capable of swimming at great speeds, but only for short distances. Scientists have studied the locomotion of the sea lamprey in order to understand the swimming action of modern fish. The lamprey uses the force of a wave against its undulating body in order to propel the fish forward or backward. Therefore, the bigger the wave, the faster the lamprey can swim. Below is an example of one complete cycle of both backwards and forwards swimming. |
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| Courtesy Model Systems in Neuroethology |
| Courtesy Locomotion of the Lamprey |
| Because the lampreys lack many of the advances of modern fishes, they are not strong swimmers. During rough conditons, the lamprey is forced to swim near the edge of streams to avoid destructive waves. The lamprey expends all of its energy in less than a few minutes of swimming and attaches itself to a rock with its oral disk in order to rest. Lacking the strength and ability to jump over barriers, lampreys are forced to swim back and forth along the barrier in order to a way around the obstacle. |