Green frog

The green frog is large. Actually, it is one of Denmark’s largest frogs. It’s also “noisy”. Green frogs croak loud and long, from May until late June. It is, of course, green, with various dark markings.

It’s actually a bit of a mystery because it really shouldn’t even exist. This is because the green frog is a cross between two different frog species: the pool frog and the marsh frog. They are two species which usually live quite a bit south of Denmark. The marsh frog can be found in a couple of places on Bornholm and Christiansø, but the pool frog isn’t in Denmark at all. Normally when two different species cross, they can’t produce eggs or young, but for some reason the green frogs in Denmark can.

Green frogs like the heat. They spend most of their lives in water, so you can try to find them in shallow lakes that get a lot of sun. They often lie on the surface of the water, with only their snout and eyes poking out, but they can also lie sunbaking on water plants and branches that have fallen into the water. The green frog has a loud croak, which sounds a bit like a machine that is trying to start. During the summer, you can also look for its tadpoles, which are unusually large – often several cm long.