This large brittlestar can be found in rockpools around much of the UK, but be gentle - its arms are very brittle and will break off if disturbed.

The large, dark grey water shrew lives mostly in wetland habitats. It's a good swimmer that hunts for aquatic insects and burrows into the banks.

The silvery dace can be seen gathering in large shoals in lowland rivers and streams. It is a member of the carp family and looks very similar to the chub, but is smaller.

The marsh hair moss is the largest moss in the UK. Look out for it in damp woodland and on boggy heathlands where it forms large, green and spikey 'cushions'.

The Migrant hawker is not a particularly aggressive species, and may be seen feeding in large groups. It flies late into autumn and can be seen in gardens, grasslands and woodlands.

As its name suggests, Water dock likes damp places, such as the egdes of canals, ponds and rivers. It is a tall plant with large, greenish flower spikes.

Living up to its name, the bullhead has a characteristically large, flattened head and a tapering body. Look out for it in fast-flowing, stony rivers and streams.

The Common walnut tree produces a large, brown nut that is familiar to so many of us. It is an introduced species in the UK, and can be seen in towns, gardens and parks.

Also known as the brown crab, this large crab is found around all UK shores and is identifiable by the distinctive pie-crust edge to its brown shell.