The nursehound is a nocturnal predator, hunting smaller fish close to the seafloor.

The chocolate-brown, plump dipper can often be seen bobbing up and down on a stone in a fast-flowing river. It feeds on underwater insects by walking straight into, and under, the water.

This shiny beetle is common in wooded areas throughout the UK. As the name suggests, it specialises in hunting snails.

Stone curlews are unusual waders with large yellow eyes - perfect for hunting beetles at night.

A breeding bird of fast-flowing, upland rivers, the grey wagtail can also be seen in lowland areas, farmyards and even towns in winter.