frog in water. pool frog crying with vocal sacs on both sides of mouth in vegetated areas. pelophylax lessonae

frog water amphibian pool crying pelophylax lessonae vocal sacs male breeding swimming plant wildlife biodiversity animal common nature call vegetation wild ecology aquatic background swim brown edible environment esculenta esculentus european amphibians green lake loud marsh front view natural outdoors pond spring summer swamp switzerland season conservation two flower water sides mouth vegetated areas