The common toad or European toad (Bufo bufo) is an amphibian. They are found in most of Europe, except for Ireland, Iceland and some Mediterranean islands. The toad usually lies hidden during the day. It becomes active at dusk and spends the night hunting for the invertebrates on which it feeds. It moves with a slow ungainly walk or a short jump. It has a grayish brown skin covered with wart-like lumps.
The toads in this genus are known as true toads. They have no teeth, a dry warty skin and horizontal pupils to the eyes.
The common toad can grow to about 15 cm (6 in) in length. Females grow larger than males. Those in the south tend to be larger than ones in the north. The head is broad with a wide mouth. The nose has two small nostrils. There are no teeth. The large, protruding eyes have yellow or copper colored irises and horizontal slit-shaped pupils. The head joins the body without a noticeable neck. There is no external vocal sac. The body is broad and squat. The front limbs are short with the toes of the front feet turning inwards. At breeding time, the male gets nuptial pads on the first three fingers. These are to hold the female. The back legs are short and the back feet have long, unwebbed toes. There is no tail. The skin is dry and covered with small warts. The color is brown, olive-brown or grayish-brown. Sometimes it is partly blotched or banded with a darker shade. The common toad tends to be sexually dimorphic. The females are browner and the males more gray.
Common toads can live for many years. They have lived for fifty years in captivity. In the wild, common toads are thought to live for about ten to twelve years. Their age can be found by counting the number of yearly growth rings in the bones of their phalanges.
The common toad usually moves by walking rather slowly or in short jumps using all four legs. It spends the day hiding. It comes out at dusk. It may travel some distance in the dark while hunting. It is most active in wet weather. By morning it has returned to its base. It may live in the same place for several months. It has a large appetite and eats woodlice, slugs, beetles, caterpillars, flies, worms and even small mice. Small, fast moving prey may be caught by a flick of the tongue. Larger items are grabbed with the jaws. Having no teeth, it swallows food whole in a series of gulps. It will try to eat any small, dark colored, moving object it encounters at night. A research study showed that it would snap at a moving 1 cm (0.4 in) piece of black paper as if it were prey. It would ignore a larger moving piece. On occasion, the common toad sheds its skin which comes away in tattered pieces. The skin is then eaten.
When attacked, the common toad puffs up its body and stands with its back end raised and its head lowered. Its main means of defense is producing a foul tasting substance and is enough to keep away many predators. Grass snakes seem to be unaffected by it. Other predators of adult toads include hedgehogs, rats and mink, and even domestic cats. Birds that feed on toads include herons, crows and birds of prey. The tadpoles also have noxious substances which keep fishes from eating them but not the great crested newt. Aquatic invertebrates that feed on toad tadpoles include dragonfly larvae, diving beetles and water boatmen. These usually avoid the noxious secretion by puncturing the tadpole’s skin and sucking out its juices.
A parasitic fly, Lucilia bufonivora, attacks adult common toads. It lays its eggs on the toad’s skin. When these hatch, the larvae crawl into the toad’s nostrils and eat its flesh.
The males arrive first and stay for several weeks. The females only stay long enough to mate and spawn. Rather than fighting for the right to mate with a female, male toads use the pitch of their voice. Croaking gives a sign of body size and prowess. Fights do sometimes happen. Male toads outnumber female toads at breeding ponds.
The female lays a long, double string of small black eggs. The male fertilizes them with his sperm. The egg strings may have 3000 to 6000 eggs and be 3 to 4.5 metres (10 to 15 ft) in length. They get tangled in plant stalks.
The strings of eggs absorb water and swell in size. Small tadpoles hatch out after two to three weeks. At first they hold onto the remains of the strings and feed on the jelly. They later attach themselves to the underside of the leaves of water weed before becoming free swimming. The tadpoles look like those of the common frog (Rana temporaria). They are a darker colour, being blackish above and dark grey below. They can be told apart from the tadpoles of other species by the fact that the mouth is the same width as the space between the eyes, and this is twice as large as the distance between the nostrils. Over a few weeks their legs develop and their tail slowly gets reabsorbed. By twelve weeks of age they are small toads measuring about 1.5 cm (0.6 in) long and ready to leave the pond.
The common toad reaches maturity at three to seven years.