 English: Common Toad Spanish: Sapo común Basque: Apo Catalan: Gripau comú Galician: Sapo común Aragonese: Zapo común Portugese: Sapo comum
Family: Bufonidae
Distribution: virtually all of Eurasia, from the UK mainland (but not Ireland) and Iberia to Siberia, and also in northwest Africa and west Asia. Found throughout Spain and Portugal, though possibly less common in the eastern and central areas and on the north Atlantic coast. A species of Bufo, a large genus of so-called “true toads” traditionally found worldwide, although some authorities have now separated the Old World species from the New.
 B. bufo is a relatively large toad with a total maximum length of about 21cm, though males are rather smaller at 9-10cm and the average female is 15cm. The head is longer than wide, with a short rounded snout, and the area between the eyes is either flat or concave. The tympanum is barely visible, measuring about half the diameter of the eye. The fingers are short, the third being the longest, followed by the the first and then the second and fourth, these latter two being of equal length. There are two tubercles on the palms. The toes are relatively long and flattened. In coloration the adult Common Toad is usually a brownish colour, but there is variation, especially in the southern part of its range. Colour variations include sand, brick-red, dark brown, grey and olive, as well as darker marks against the overall tone. The underside is whitish or grey, often with a marbled effect. The eye is copper or gold.
(For a guide in identifying frogs and toads which explains these terms, click on the link). Bufo bufo can be distinguished from Bufo calamita (also present in Iberia) by the shape of the paratoid glands. [Look to the rear of the eyes. There may be a raised area on both sides of the head containing pore-like openings. These areas are known as the parotoid glands. Not only can their presence be a key to the species, but also their shape, since in some species the gland area is straight and in others bent inwards.] In Bufo bufo these are kidney-shaped, bending inwards somewhat in the middle, while in Bufo calamita they are straight, being further apart at the front than at the back. B. calamita normally also has a thin yellow stripe down the back which is lacking in B. bufo. Bufo calamita also goes by the scientific name of Epidalia calamita.
The huge range of this species has already been noted, signifying also a broad tolerance to climatic conditions since it is found from northwest Africa to Scandinavia. In Iberia it is found at up to 1,870m in Portugal and 2,000m in the Pyrenees and Sierra de Gredos.
Like most European amphibians the Common Toad feeds on a variety of invertebrates. In Spain beetles, ants, centipedes, millipedes, spiders, grasshoppers and related insects have been cited as part of its diet, as well as occasionally rodents (presumably mice, voles or similar small species), a reminder that these toads are relatively large. However one observer states that they do not eat slugs.
The toad is normally a nocturnal animal, although it can be found abroad during wet weather or in the breeding season. I once encountered a pair in amplexus in my patio garden in rainy weather, the pair making little or no attempt to move. [Amplexus = The copulatory embrace of frogs and toads, during which the male fertilizes the eggs that are released by the female.] Otherwise they tend to favour a particular spot to shelter in (one authority mentions hiding beneath stones) and appear at dusk. Unlike frogs, Common Toads rarely hop but prefer to walk. They have two effective anti-predator devices: bufotoxin, a white milky substance which is secreted via the paratoid glands behind the eyes and which is extremely distasteful to many predators, and the defensive pose in which they stand erect on their limbs and swell their bodies up to make themselves appear much bigger. This defence may be especially useful against the Grass Snake (Natrix natrix) since the latter is not bothered by bufotoxin.
 Note the copper coloured eye of these Common toads in contrast to the pale eye of the Natterjack toad.
Breeding: Common Toads are noted for their migrations towards their home ponds, a process which may begin in the autumn but which peaks in spring. At this time they are most vulnerable to road traffic, which in the past has taken a high toll: in some European countries conservation measures and volunteer support are now in place. Males arrive first and can remain for some weeks (3-28 nights) in the ponds, whereas females may make just a short visit (3-6 nights) to find a mate and lay their eggs. Mating itself is a rough-and-tumble affair. Since males usually outnumber females by four or five times they must fight for mates and often end up clasping different species, fish or even inanimate objects, or else several home in on one female and form a breeding “ball”. Males clasped by other males have a special “release call” to notify the offender of his mistake! Needless to say this level of competitive activity is stressful for all the participants, and toad mortality is quite high as a result. Females lay 3,000-8,000 eggs in two strings which they lay simultaneously over the course of up to several hours, depositing these on aquatic vegetation often in places where there is good sunlight. The eggs develop within 2-3 weeks and the resultant tadpoles form large swarms. At metamorphosis they are 7-12mm long and more diurnal than the adults. The breeding season varies according to range. In Portugal it lasts between November and April but lasts until June in the high mountains of the Gredos. Sexual maturity also varies with latitude, taking 3-7 years in northern Europe but in Iberia 3 years for males and 4 for females. Occasionally hybrids of B. bufo and B. calamita or (elsewhere in Europe) B. viridis are encountered. In most of Europe B. bufo has a winter rest period from October-November until February-March. Most spend this period on land rather than in water. The huge range of the Common Toad would appear to make it fairly safe, but like all amphibians it is faced with the threats of habitat loss, chemical pollution and, more seriously, long-term climate change. As a species it has often been persecuted in the past by humans, partly because of a cultural association with its use by witches. Despite the bufotoxin to deter casual predators, Bufo bufo is also preyed on by various birds of prey (eagles, buzzards, kites, and owls) and the Grass Snake ( Natrix natrix). The fly Lucilia bufonivora also causes depredation by laying its eggs on the toad's back. The ensuing larvae migrate to the nasal cavities of the toad and feed on the tissues in this area, causing the death of the host within 2-3 days. One authority states that adult populations have a complete turnover of 4-5 years, ie a loss rate of 25% of adults each year. SubspeciesDespite the enormous range of the Common Toad, there are only 3 subspecies, 1 of which is confined to Spain. Bufo bufo bufo : nominate subspecies, found across virtually the entire range but especially the northern parts. Bufo bufo gredosicola : found in the Sierra de Gredos in Spain. Characterised by very large paratoid glands. Bufo bufo spinosus : Mediterranean area. Characterised by spinier skin and very large size.
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