Common Frog

Cold-proof from pond to Arctic

This frog copes well with cold climates. The common frog (Rana temporaria) lives across Great Britain, Europe and northwestern Asia, and Animal Diversity Web says it reaches the Arctic Circle in Scandinavia. In Britain it gets through winter tucked under rocks, in compost heaps, or down in the pond, buried in mud and plants. Froglife says it does not hibernate as such, and on a mild day it may pop out to forage.

Small, smooth and many-coloured

In Britain, males grow up to 9 cm long and females up to 13 cm. Animal Diversity Web gives an average mass of 22.7 g. The skin is smooth and the legs are long, built for jumping away fast. They are usually olive-green or brown with a dark mask behind the eye, but yellow, pink, red, lime-green, cream and black frogs turn up too. In breeding season males develop blue patches on the back and throat.

Pond rafts Froglife says a British spawn raft often holds up to 2,000 eggs, each small black egg wrapped in a clear jelly capsule about 1 cm across.

A fast spring

In Britain, adults leave their winter spots in early spring and head straight to a pond. Males may piggyback on a female on the way there. Eggs go in as early as January in south-west England, and two to four weeks later, depending on the weather, the tadpoles hatch. Tadpoles start black, then pick up gold-brown speckles. They eat algae and water fleas. After about 16 weeks they grow back legs, then front legs, and leave the water as tiny froglets, usually in early summer. Frogs reach breeding age at 2 to 3 years old. AnAge lists 27 years as the maximum longevity for the species, and says frogs in the wild may live up to 14 years.

Night shift hunters

Adults mostly feed at night on a wide variety of invertebrates, especially slugs and snails. Away from breeding time, a frog may wander as far as 500 metres from its pond. They find worms by smell. The common frog is rated Least Concern by the IUCN, but Froglife lists habitat degradation and introduced disease as threats, and calls garden ponds extremely important to it, especially in towns.