Added 3 August 2003.
Frogs and Toads of Europe: True Toads
The Family Bufonidae are distributed worldwide, being absent only from polar areas, some Pacific islands and Madagascar. They belong to the Neobatrachia, or "new frogs". The genus Bufo alone has well over 200 species, but perhaps surprisingly, only 3 are found in Europe: however, this trio enjoys a fairly wide and abundant distribution.
Bufonidae are medium- to large-sized toads, usually with a large set of parotid glands above the ears. The ear is usually visible and the pupil tends to be horizontally elliptic. Although not all toads are warty in appearance (contrary to popular belief), those in Europe certainly are. All the European species also have webbing between their toes. Males can be distinguished by their smaller size, and those which are sexually mature by the nuptial pads on the insides of the first three fingers which turn dark during the mating season.
NB Unlike the pages for the other Reptile and Amphibian families, where measurements were given in inches or feet, measurements for the families here are given in centimetres, owing to the generally small size of the subjects.
Either click on a frog or toad in the Quick Links section or scroll down for the whole table.
| Scientific Name |
Common Name |
Distribution |
Size |
Notes |
| Family BUFONIDAE |
| Bufo bufo |
Common Toad |
Europe (inc. GB), temperate Asia, Japan: absent from Ireland and Malta, Corsica, Sardinia, Crete and the Balearic islands. |
10-15 cm |
One of the most widely distributed anurans in the world, stretching across half the globe, yet in danger of severe depletion at the hands of man due to roadkills or general antipathy, despite its usefulness as a consumer of various nocturnal insects, larvae and molluscs. Sexual dimorphism in the Common Toad is very marked, with the females being obviously larger. Most of the year round these toads are solitary creatures and somewhat territorial, excavating their own refuge and having their own hunting territory. However when the breeding season begins in spring (usually end of March in C. Europe) Common Toads travel in their hundreds to their breeding ground, usually a pond in a wood or field, which is often a long distance away - hence the casualties on the roads. If the water covers a large area, the toads remain in a narrow zone at the water's edge. The males make rather muffled calls which travel just far enough to allow the females to locate potential partners. (The males do not have external resonators to amplify their calls, unlike many other anurans). After ampiplexus the females lay up to 6,000 eggs each in strings that can reach over 2 metres in length. The period from hatching to metamorphosis lasts 2-3 months: the tadpoles form shoals and feed on algae. Common Toads can be distinguished from the Natterjack and Green Toad, also members of the Bufo genus, by the shape of its parotoid glands behind its eyes: in the Common Toad the glands are crescent-shaped, while in the other European toads they are straight. |
| B. b. bufo |
|
Throughout practically the entire range of B. bufo |
|
| B. b. gredosicola |
|
Central Spain, Sierra de Gredos |
|
Some doubt has been raised about the status of this subspecies. |
| B. b. spinosus |
|
Mediterranean regions |
|
Nöllert and Nöllert note that there seems to have been considerable hybridisation with B. bufo bufo in Portugal, C & S France, the southern Alps and the northern part of the Balkans. In the latter area the classification of the spinosus subspecies may be somewhat tenable. |
| Bufo calamita |
Natterjack |
Iberia, W. Europe (inc. GB), Czechoslovakia, Poland, Baltic |
5-8 cm |
The Natterjack is distinctly smaller than its fellow Bufo species the Common and Green Toads and can also be distinguished from the Common Toad by its green, as opposed to yellow, irises. In addition it has a yellow stripe running down its back. Due to its hindlegs being about the same length as its forelegs, the Natterjack runs instead of leaping. Its favourite habitats are found in countryside made up of unfertile soil on a sand or clay base. Populations tend to be small and this toad is nocturnal, soberly coloured and small, so the Natterjack is not often noticed by the casual observer. However, the call of the male in the mating season is quite loud and can reach females some way away. In late spring or early summer the female lays 3,000-4,000 eggs in single or double strings. These are deposited in small pools which dry up: this has the result of causing the larvae to develop quickly. Interestingly larvae near the sea will also develop in brackish water. Diet (mainly insects) and behaviour of the Natterjack are similar to the other Bufo species. |
| Bufo viridis |
Green Toad |
Europe (exc. Iberia, GB and part of France) east to Mongolia, south to N. Africa and SE to Arabia |
10 cm |
The Green Toad is a handsome amphibian, slimmer and longer-limbed (and thus nimbler and faster) than the Common Toad and larger than the Natterjack. It is also quite tough, being able to survive droughts and high temperatures by sheltering in hideouts that it excavates for itself, and is less fussy than many amphibians about water quality, apparently being able to utilise polluted village ponds or even parts of a sewer. It can be found on seashores, dry steppes or in damp areas, and is not shy of approaching human habitations to catch insects attracted by lights. Although in Asian mountains it can be found at up to 4,500 m, the European populations evidently prefer low country. Of the subspecies of this toad, the European form is the nominate subspecies. The females are larger and plumper than the males. The latter have a visible vocal sac and make mating calls that have been described as "tinkling" or "trilling": these calls are only made in the water. Although breeding takes place in April-May, some males will carry on calling into June. The female lays 12,000 eggs wrapped in gelatinous strings 2-4 metres long: the tadpoles hatch in 4-5 days and develop in 2-3 months. They become the largest tadpoles of the European Bufo species before metamorphosis. The different Bufo tadpoles can be distinguished mainly by size and the shapes of their mouths. Occasionally hybrid forms of the Natterjack and Green Toad are encountered. |
| B. v. viridis |
| B. v. balearicus |
Mallorca, Minorca, Ibiza |
According to Nöllert and Nöllert, these toads were probably brought into the Balearic Islands from Corsica and Sardinia during the Bronze Age for cultic reasons. They believe the subspecies status is not justifiable as there has been insufficient time for the Balearic toads to develop subspeciation. |
Bibliography
I would like to acknowledge the crucial part played in this page by Lanka and Vit's Amphibians and Reptiles, from which accounts of the more obscure frogs were sometimes lifted almost verbatim. Any mistakes are my own! Data will be added or corrected in the course of my further reading.
Reptiles and Amphibians, Vaclav Lanka and Zbysek Vit, Hamlyn Colour Guide, Prague, 1985
Die Amphibien Europas, Andreas and Christel Nöllert, Franckh-Kosmos, Stuttgart, 1992.
Reptiles and Amphibians of Britain and Europe, E N Arnold, J A Burton, D W Ovenden.
The Common Toad, Dr Fred Slater, Shire Natural History, Buckinghamshire 1992. Very useful guide to Bufo bufo in Britain, also drawing on European data. The Shire series in general contain some very inexpensive gems of information on British wildlife.
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