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Shannies are a small, rock-dwelling species which thrive in British waters. You will find them in every single rocky environment where the water is salty. You can distinguish shannies from blennies by looking at their heads. Blennies have a tentacle-like fringe which shannies don‘t possess.

Looking at how creatures have adapted to their environment requires the young scientist to be a bit of a detective so let’s compare your answers with the ones below and see how you rate your own detective work. Did you get the main points correct? Shannies are usually a mottled brown, green or grey. Why?

These are colours which blend in with the rocks and weeds where they live, providing the fish with excellent camouflage. They are much harder to spot in these colours than if they were brightly coloured, which would make them stand out like a sore thumb.

Shannies tend to swim close to the rocks, with their bodies virtually, if not actually, touching the rocks. Why do you reckon this is?

Their predators, like bass, are able to detect the swimming motion of other fish. When smaller fish swim by they send out ripples – vibrations – in the water which are detected on the predator’s lateral line, which is basically a series of nerve endings. However when smaller fish hug the rocks the vibrations they send out are confused by the rock – bounced all over the place – so that the fish becomes difficult to find. If a blenny suddenly stays still, squeezed tight against a bigger rock, he becomes very, very difficult to find. If he pops inside a hole in the rock he becomes almost impossible to spot, let alone reach.

Shannies have powerful teeth and strongly muscled jaws. Why do you think these features are important?

If shannies use the rocks in which they live for protection, then they cannot go far out of their way for their lunch. This means that their most plentiful food supply is going to be shellfish, such as winkles, or crustaceans such as shore crabs or hermit crabs. They will, of course, eat smaller fish if they get the chance, as well as feeding on carrion, but their powerful jaws mean that they can crunch up crustaceans or shellfish without hurting themselves in the process.