The two northern species are partially migratory, with many birds moving south to warmer areas in winter.

The horns also make the animals a prized game trophy, which has led to the near-extinction of the two northern species.

This lamprey is the most common of the northern European species and is also the smallest.

The three northern species are sometimes known as ground-warblers.

These are mainly resident birds, but the northern species at least will sometimes move south or to lower altitudes in autumn.

Most live in deep water, except a few more northern species.

Some northern species may hibernate in these burrows throughout the winter.

The northern species, the Florida short-faced bear was extinct 11 000 years ago.

They are effectively southern species coming north to breed rather than northern species going south to winter.

But at the same time several northern species are moving south.