Lamprey are prehistoric fish that have been around for millions of years. They have a long snake-like appearance and have 7 pairs of breathing holes instead of gills. There are three types that live in the River Eden: brook lamprey, river lamprey and sea lamprey. The sea lamprey is the biggest and can grow to 120cm long. Lamprey are vertebrates but don’t have a bony skeleton, and are jawless, meaning their mouths are always open.

Sea lamprey are parasites. They attach themselves to other animals and feed off their flesh and internal organs using mouths that are well designed for this purpose. Concentric rows of hooked teeth latch on to their victim while their piston-like tongue drills and scrapes through the skin of the prey until the lamprey can suck its blood or even its intestines. Thankfully, lamprey attacks on humans are very rare!

Lamprey are very efficient swimmers and use the turbulence created by the movement of their bodies to move pebbles for their nest, called a ‘redd’.