Green Frogs including Edible Frog /Marsh Frog (Pelophylax esculentus)
These are non-native frogs which often breed (and call) during the summer months. The term ‘Green Frog’ encompasses a complex of similar species including the Marsh Frog Pelophylax ridibundus, Edible Frog P. esculentus and Pool Frog P. lessonae. The Pool Frog is a native species which became extinct in UK and has since been reintroduced to East Anglia. Green frogs are variable in colour but often have a yellow stripe down the back; they usually lack the ‘mask’ behind the eye that the Common Frog has. The nose is relatively pointed and the eyes are closer together than the common frog. Unlike American Bullfrogs, another non-native species, green frogs have a pair of conspicuous dorsolateral ridges running the length of the body. When calling, green frogs inflate a pair of vocal sacs, rather like a pair of balloons, one either side of the head; all have a loud call which is often likened to ducks quacking. Marsh Frogs can be up to 15cm long but other species smaller.
| Identification | Adult marsh frogs up to 15cm in length. Adult edible frogs are smaller. Green frogs are variable in colour (light brown through to dark green). Often have a yellow stripe down the back. Lack a ‘mask’ behind the eye as seen in the Common Frog. Pair of raised ridges running down both sides of the body.Males have visible vocal sacs.
Call: loud and likened to ducks quacking or rapid laughter. |
| Distribution | Non-native species. Native to Europe: widespread and common in Europe. Populations found in southern areas of England. |
| Ecology | Lay small ‘rafts’ of spawn. Individual eggs are brown on top and yellowish underneath. |
| Predators and other threats | The Marsh Frog Pelophylax ridibundus is predated by herons, Grass Snakes and cats both in the UK and in its native ranges. Its conservation status is classified as being of Least Concern on the IUCN website and the population trend for this species is increasing.
The Edible Frog Pelophylax esculentus is also consumed by herons and related species and Grass Snakes in the UK and wider Europe, and is a largely aquatic species. In its native ranges, it is generally threatened by aquatic pollution (often by agrochemicals) and drainage of wetland habitats. According to the IUCN website, the frog-leg trade and high levels of pollution are leading to significant declines in populations in former Yugoslavia. |
N.B. The release of exotic species into the wild is a criminal offence under the Wildlife and Countryside Act 1981.