Pelophylax kl. esculentus
Edible Frog
Identification: Length up to 12 cm, mostly smaller than 10 cm. Females larger than males. Hybrid of Marsh Frog and Pool Frog. Intermediate in general appearance. Back light- to dark green or brownish with scattered dark spots. Sometimes the animals are totally brown, but the side of the head is usually still green. Usually there is a light green stripe over the middle of the back. They seldom have a coarse skin like the Marsh Frog. On the border of the flank and back, there are dorsolateral folds, which alternate just in front of the hind legs. Back of thighs yellowish or orange with irregular, dark bars and spots. Belly whitish with grey to brown marbling. Well-developed webbing on the relatively long hind legs. Rather large and high asymmetric metatarsal tubercles (up to half the length of the toe on which the metatarsal tubercle is standing). Males with thicker front legs, grey nuptial pads on the thumbs and white to grey vocal sacs.
Range: Mid and northeast Europe as far as Russia. In the British Isles, there are some small colonies in southern England that were probably all introduced. Many other small introductions have been attempted, as in Surrey and Yorkshire, but most of these do not survive long.
Habitat: In several habitats in all sorts of waters with exposure to the sun, well-overgrown borders and shallow parts, varying from ponds in woods to ditches, lakes and rivers. Sometimes in brackish water too.
Habits: They leave their hibernation quarters usually from mid-March onwards. Mainly diurnal, but in the breeding season also active at night. Basks extensively during the day. Stays mostly in the water, but goes on land to forage, mainly at night. Is often the most numerous green frog. Often occurs in mixed colonies with Pool Frogs but is more restricted to water than this species. In the breeding season (highest activity in May and June), the males often call in dense associations. Eggs are laid from April to mid-July, the most around mid-May. A female lays 3000-8000 eggs in a season. Newly hatched larvae measure 5-8 mm and grow up to about 5-8 cm. Development of the larvae takes 2-4 months. Most of them metamorphose between mid-August and mid-September. The frogs are 2-2.5 cm long then, and they mature after 2-3 years. Juvenile Edible Frogs migrate up to several kilometres. Usually hibernates dug into the soil on land, sometimes under water.
How to find: The best chance is in breeding season (May to July). The animals gather together and form large, dense and loud associations. Calls mainly in the evening, but on warm, sunny days also during the day.
Call: Series of grunting or rattling sounds, increasing and decreasing "rè - rè - rè". Each call takes about 1.5 seconds. The pulses follow less quickly than in the Pool Frog.