These well-known amphibians are smooth and slippery masters of disguise. The common frog is a regular visitor to our canals.
Frog eyes and nostrils are on top of their head so they can see and breathe when swimming.
Frog facts
Scientific name: Rana temporaria
Family: Ranidae
Diet: Insects, snails, worms, and slugs. Tadpoles feed largely on algae
Predators: Herons, foxes, otters, snakes, birds of prey, and cats
Size: 6-10cm. Females are usually slightly larger than males
Weight: 22g
Lifespan: 5-10 years
About frogs
Frogs are amphibians, meaning they're cold-blooded and can't function when temperatures drop too low. Therefore, common frogs in the UK hibernate during the winter under logs or at the muddy bottom of a pond. Able to absorb oxygen through their thin skin, frogs can happily spend several months underwater, beneath piles of mud or leaves.
In the UK, the common frog is our main resident species. However, there have been recent attempts to reintroduce the northern pool frog – a native species presumed extinct in 1995.
Frogs and our canals
Common frogs are widespread throughout the UK, but they're perhaps not as common as they once were.
These amphibians rely on water habitats to breed and sometimes hibernate. Our canals provide safe, natural corridors for frogs to make their homes and travel to water bodies in the breeding season.
The common frog has a sturdy body with strong back legs for jumping and webbed toes to swim. They can vary in colour, from olive green, grey, and brown to more exotic-looking red and yellow individuals. Sightings of pink, orange, and even albino frogs have also been reported. They're able to adapt their skin colour to their surroundings.
Common frogs have very smooth skin with irregular dark patches and a dark band around the eyes. The eyes and nostrils are on top of the head, so they can see and breathe (through their nose) when the rest of their body is underwater.
Tadpoles are brown, becoming speckled and golden as they grow.
A common frog with smooth skin, irregular dark patches, 'masks' around the eyes, and banks on the hind legs.
What do frogs eat?
The common frog is carnivorous. Using long, sticky tongues to catch invertebrates, frogs survive on a diet of flies, worms, snails, and slugs. They've also been known to eat smaller amphibians, and when they moult, frogs eat the skin for nutrition. Tadpoles are herbivorous, eating algae.
Despite their wide mouths, frogs drink water by absorbing it through their skin. They swallow food by retracting their eyes into their heads to push it down their throats.
How do frogs breed?
Frogs begin breeding in early spring, heading to bodies of water, like ponds, lakes, and canals, to mate. To attract a female, the male will croak louder than the competition. When successful, he uses swollen 'nuptial pads' on the front feet to grip the female – known as 'amplexus'.
Females can lay up to 2,000 eggs in a clump, known as frogspawn, in well-vegetated, shaded, and shallow water – although few survive. The tiny black dots in the clear jelly are developing frogs. It can take anywhere from a few weeks to months for the dots to get longer, taking on an eel-like appearance and turning into a true tadpole.
Once emerging from the frogspawn, tadpoles will eat it before moving on to other food sources. They take up to 16 weeks to lose their tails and grow legs, becoming froglets.
The black dot at the centre of the frogspawn is the developing tadpole.
Where do frogs live?
Outside of the breeding season, frogs spend most of their time on land. They can be spotted among tall plants in meadows and woodland. On warm, damp evenings, they come out to hunt prey.
In the spring, frogs become aquatic. They breed in any area of still, shallow water, including puddles, ponds, streams, lakes, and canals.
During winter, common frogs hibernate at the bottom of a pond or under a pile of logs.
Despite the name common frogs, these creatures aren't as common as they once were. Still, you might be able to spot one of our most-loved amphibians near your local canal or garden pond.
What's the best time of year to spot frogs?
Spring is the best time to spot frogs as they journey to bodies of water for breeding. Listen for their deep croaks – a courtship ritual – and look for frogspawn in the water.
What's the difference between frogs and toads?
Although both small amphibians, frogs and toads are different species. You can tell them apart by the way they move. Frogs (pictured left) have long legs for jumping, while toads (pictured right) have shorter legs and prefer to crawl.
Frogs also have smoother, slimy skin, whereas toads are dry and warty.
Threats to frogs
The common frog might be widespread in the UK, but populations have declined in recent years. The main threat to frogs is the loss of breeding habitats as small ponds are filled in and urban development cuts off routes to bodies of water.
Our canals provide connected habitats for frogs and other wildlife throughout urban and rural spaces.
