The marsh frog is Europe’s largest native frog (15cm long), with warty, spotty skin and a pointed snout.

Its vocal sacks allow it to make a variety of croaks and chuckles. It is most noisy during the breeding season, although it will continue to sing throughout the summer. Each individual frog changes its calls erratically, showing that the marsh frog has one of the most complex songs of all European amphibians.

Frogs do not have "voices" as such, but thanks to their vocal sacks which pull air in and out of their lungs, they developed their croaks, which fulfil the same role for them as birdsong does for birds.

Marsh frogs, although not native to Britain, were introduced to Romney Marsh from Hungary in 1935. They have now spread into the surrounding areas of Sussex and Kent, but, despite being larger, do not seem to have harmed the native population.