The common frog, Rana temporaria, peering out of a duckweed-covered pond. R. temporaria is found throughout Europe. It spawns early in February and March and is well known for returning to the same breeding ground year after year to do so. Large groups of frogs gather and in a period of one to three nights lay their eggs in densely packed masses. What triggers this meeting to breed is unknown since this species only utters a soft purring sound similar to a cat. Outside the breeding season the frogs are found in forests and damp meadows, usually several hundred metres from the breeding site.