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

frog water vocal sac male amphibian pool crying pelophylax lessonae sacs breeding swimming plant wildlife biodiversity animal brown green common noise nature call wild croaking sound ecosystem aquatic beauty swim vegetation environment leaf esculenta esculentus backgrounds loud marsh outdoors pond spring summer swamp switzerland one reserve natural water sides mouth vegetated areas