The sea hare looks like a sea slug – but in fact has an internal shell. They can be up to 20cm long but are usually much shorter.

This large shieldbug lives up to its name, bristling with long pale hairs. It's a common sight in parks, hedgerows and woodland edges in much of the UK.

A tall and robust species of sedge, the Great fen-sedge has long leaves with sawtooth edges. It forms dense stands in lowland fens and around lakes.

Native oysters are a staple of our seas and our plates - but our love of their taste has lead to a sharp decline all around the UK.

Although introduced by humans, the fallow deer has been here so long that it is considered naturalised. Look out for groups of white-spotted deer in woodland glades.

The song of the Roesel's bush-cricket is very characteristic: long, monotonous and mechanical. It can be heard in rough grassland, scrub and damp meadows in the south of the UK, but it is…

The variable damselfly looks a lot like the azure damselfly, but is much less common throughout most of the UK.

The long mane of tentacles that stream out from the lion's mane jellyfish is stunning… literally! Look but don't touch when it comes to these jellyfish - they give a powerful sting.

When spotting the pintail in winter, look out for the fabulous, long tail feathers that characterise it. This dabbling duck feeds at the water's surface, rather than diving for food.

Red squirrels are native to the UK but are a lot rarer than their grey cousins. They live in a few special places across the UK thanks to reintroduction projects.