The marsh frog (Pelophylax ridibundus) is a species of water frog native to Europe and parts of western Asia. The marsh frog is the largest type of frog in most of its range, with males growing to a size around 100 mm (3.9 in) SVL and females slightly larger (4 in) SVL. There is a large variation in colour and pattern, ranging from dark green to brown or grey, sometimes with some lighter green lines; a lighter line on the back is generally present. The frog will usually be darker coloured in early spring to absorb heat more efficiently. (Source: Wikipedia.org, CC BY-SA)