Habitat or Species Feature, February 2022

UK Conservation Status: GREEN but declining in some parts of the country

Most of us have a childhood memory of tadpoles, probably in a jam jar or fish tank at primary school. Perhaps you have a pond in your garden and have seen frogs and frog spawn there.

Frogs are often found close to fresh water in habitats that remain damp throughout the summer. Outside of the breeding season they can roam up to 500 metres from a breeding pond.

Common frogs have smooth skin and long legs for jumping away quickly. They tend to be most active at night when they feed on insects, slugs and worms. They are a gardener’s friend.

Spawning takes place during early spring, starting in the south of the UK as early as January.

Adult males grow up to 9 cm in length and females up to 13 cm. Frogs reach breeding age at 2-3 years old. Males may ‘piggy back’ to the pond on the larger female. In the breeding season you may hear the soft croaking of the males looking for a female.

‘Rafts’ of spawn are deposited in a pond, often containing up to 2000 small black eggs each surrounded by a clear jelly capsule around 1 cm across. The tadpoles are black when they hatch but develop light bronze speckles as they mature.

The tadpoles feed on algae and water fleas. They generally take up to sixteen weeks to grow back legs, then front legs, before they metamorphose into tiny froglets, ready to leave the water in early summer (often June, but in some ponds this may be as late as September).

Common frogs spend the winter sheltering under stones, in compost heaps or at the bottom of ponds. They don’t hibernate as such, and may take advantage of milder patches of weather to come out and search for food.

Since the late 1980s a deadly disease has affected frogs in England – ranavirus. The disease has spread northwards and many frogs have died. The disease has no cure, but resistant frogs have survived and bred successfully. For more information on this disease check out the Froglife website.

How do I tell the difference between frogs and toads?

Adult frogs have smooth, moist skin and long, stripy legs, hop or jump around and are likely to be found in damp habitats in the garden. Toads have warty skin, golden eyes and prefer to crawl rather than hop; if threatened a toad can puff itself up to appear bigger. Toads can tolerate drier habitats than frogs and spend less time in water.