It is found in France, the Iberian Peninsula and the Maghreb and grows to a larger size and has a spinier skin than its more northern counterparts with which it intergrades.

[6] It is believed that the range of the ancestral form extended into Asia but that isolation between the eastern and western species complexes occurred as a result of the development of the Central Asian Deserts during the Middle Miocene.

Nine to thirteen million years ago, Bufo eichwaldi, a recently described species from south Azerbaijan and Iran, split from the main lineage.

Further divisions occurred with Bufo spinosus splitting off about five million years ago when the Pyrenees were being uplifted, an event which isolated the populations in the Iberian Peninsula from those in the rest of Europe.

[15] The common frog (Rana temporaria) is also similar in appearance but it has a less rounded snout, damp smooth skin, and usually moves by leaping.

It spends the day concealed in a lair that it has hollowed out under foliage or beneath a root or a stone where its colouring makes it inconspicuous.

It is voracious and eats woodlice, slugs, beetles, caterpillars, flies, ants, spiders, earthworms and even small mice.

[21] In 2007, researchers using a remotely operated underwater vehicle to survey Loch Ness, Scotland, observed a common toad moving along the bottom of the lake at a depth of 324 feet (99 m).

[28] When attacked, the common toad adopts a characteristic stance, inflating its body and standing with its hindquarters raised and its head lowered.

Aquatic invertebrates that feed on toad tadpoles include dragonfly larvae, diving beetles and water boatmen.

[34] Toads experimentally moved elsewhere and fitted with tracking devices have been found to be able to locate their chosen breeding pond when the displacement exceeded three kilometres (two miles).

[15] A successful male stays in amplexus for several days and, as the female lays a long, double string of small black eggs, he fertilises them with his sperm.

[41] A comparison was made between the growth rate of newly metamorphosed juveniles from different altitudes and latitudes, the specimens studied being from Norway, Germany, Switzerland, the Netherlands and France.

[43] This type of sperm senescence does not occur at a genetically fixed rate, but rather is influenced by environmental conditions that include availability of mating partners and temperature.

It is not particularly threatened by habitat loss because it is adaptable and is found in deciduous and coniferous forests, scrubland, meadows, parks and gardens.

The major threats it faces include loss of habitat locally, the drainage of wetlands where it breeds, agricultural activities, pollution, and mortality on roads.

Chytridiomycosis, an infectious disease of amphibians, has been reported in common toads in Spain and the United Kingdom and may affect some populations.

A population in the Sierra de Gredos mountain range is facing predation by otters and increased competition from the frog Pelophylax perezi.

The researchers demonstrated this by genetic analysis and by noting the greater number of physical abnormalities among urban as against rural tadpoles when raised in a controlled environment.

It was considered that long term depletion in numbers and habitat fragmentation can reduce population persistence in such urban environments.

Many of the deaths take place on stretches of road where streams flow underneath showing that migration routes often follow water courses.

[46] In some places in Germany, Belgium, the Netherlands, Great Britain, Northern Italy and Poland, special tunnels have been constructed so that toads can cross under roads in safety.

In other places, local wildlife groups run "toad patrols", carrying the amphibians across roads at busy crossing points in buckets.

The skin of the South American cane toad contains enough similar toxin to cause serious symptoms (or even death) in animals, including humans.

[52] Clinical effects include severe irritation and pain to eyes, mouth, nose and throat, cardiovascular and respiratory symptoms, paralysis and seizures, increased salivation, vomiting, hyperkalemia, cyanosis and hallucinations.

Between 1610 and 1612, the Spanish inquisitor Alonso de Salazar Frías investigated witchcraft in the region and searched the houses of suspected witches for dressed toads.

[55] An English folk tale tells how an old woman, a supposed witch, cursed her landlord and all his possessions when he demanded the unpaid rent for her cottage.

[54] The First Witch in Shakespeare's Macbeth gave instructions on using a toad in the concoction of spells:[57] Round about the cauldron go; In the poison'd entrails throw.

Toad, that under cold stone Days and nights has thirty-one Swelter'd venom sleeping got, Boil thou first i' the charmed pot.

It was also believed that there was a jewel inside a toad's head, a "toadstone", that when worn as a necklace or ring would warn the wearer of attempts to poison them.