Introduction
Of the more commonly found frog species within the British Isles, there are two groups:
- Brown frogs, including the Common frog and Agile frog.
- Green frogs (or Water frogs), which include the Pool frog, Marsh frog and Edible frog.
These three species of Water frog are capable of interbreeding. As they are so closely related, differentiating between the species can be difficult. This web page explains the differences.
Morphological Differences
This section compares the differencies in form and structure between the water frog species.
Key differences between species:
| Feature | Pool frog (Pelophylax lessonae) |
Edible frog (Pelophylax kl. esculentus) |
Marsh frog (Pelophylax ridibundus) |
|---|---|---|---|
| Size: | 42mm - 71mm (~2.2 inches) | 54mm - 89mm (~2.8 inches) | 74mm - 94mm (~3.3 inches) |
| Male call: |
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| Vocal sacs: | The male Pool frog has white vocal sacs. | The male Edible frog has light grey vocal sacs. | The male Marsh frog has dark grey vocal sacs. |
| Metatarsal Tubercles: |  |
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| Hind leg length: |
Of the three species, the Pool frog has the shortest hind legs in comparison to its size. When the hind leg is compared to body length, the heel reaches behind the eye. |
Of the three species, the Edible frog has hind legs that are longer than the Pool forg, yet shorter than the Marsh frog in comparison to its size. When the hind leg is compared to body length, the heel reaches between the eye and snout. |
Of the three species, the Marsh frog has the longest hind legs in comparison to its size. When the hind leg is compared to body length, the heel reaches beyond the snout. |
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