The gudgeon is a bottom-dwelling fish, similar to the stone loach, but with only two whisker-like barbels near its mouth. These sensory organs help it to find its prey in the sand and gravel of…

The common name of the bloody-nosed beetle derives from its unusual defence mechanism: when threatened, it secretes a distasteful blood-red liquid from its mouth. This flightless beetle can be…

The river lamprey is a primitive, jawless fish, with a round, sucker-mouth which it uses to attach to other fish to feed from them. Adults live in the sea and return to freshwater to spawn.