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Description
A medium to large toad. Parotoids behind the eyes are prominent. Pupil of the eye is horizontal. Tympanic membrane not visible. No male resonator. No tarsal fold. 2nd and 3rd toes with paired subarticular tubercles. Dorsal skin usually with rounded tubercles, sometimes with sharp top. Dorsal surface white-grayish, gray, brown or olive-brown with more or less developed darker spots. These spots are sometimes absent, sometimes fused into irregular longitudinal bands. Background coloration changes during the breeding season, becoming uniform. Belly light-gray or yellowish-gray with dark spots.
Male differs from female in having nuptial pads on 1st finger (during the breeding season on 1st, 2nd and/or 3rd fingers), smaller body size and in some body proportions. In the Carpathian Mountains, sexual differences in toad breeding coloration have been described: males have uniform, light-greenish-brownish dorsal coloration, whereas females are more brown with dark-brown spots which sometime fuse into irregular longitudinal bands most distinct on the flanks.
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Albania, Austria, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Gibraltar, Greece, Hungary, Italy, Kazakhstan, Latvia, Liechtenstein, Lithuania, Luxembourg, Macedonia, the Former Yugoslav Republic of, Moldova, Republic of, Montenegro, Netherlands, Norway, Poland, Romania, Russian Federation, Serbia, Slovakia, Slovenia, Sweden, Switzerland, Turkey, Ukraine, United Kingdom
The species is widespread in Europe.
Northern margin of its range extends from Norway and Sweden (ca. 65-67oN) to Northern Finland (Saariselka, Muanio and Kittila at 68° N to Northern Russia: from the northern coast of the White Sea in Murmansk Province (Kandalaksha Nature Reserve: 66° 35'N, 33° 13'E) and covers the whole of Karelia. It occurs through Arkhangelsk Province (from the environs of Arkhangelsk City:
64° 36'N, 40° 32'E to Pinezhskii Nature Reserve), then approximately along
the line Komi Republics - through Urals to Tyumen Province (Yamal-Nenets
Autonomous County) - Krasnoyarsk Region (middle flow of Enisei River). Then
it turns south-south-eastwards to the Chuna River in Krasnoyarsk Region and
Irkutsk Province in the East Siberia. The easternmost known locality is
Kunerma Settlement in Kazachinsko-Lensk District of Irkutsk Province
(56° N, 108° 30'E). Thus, the major part of the northern margin of the
range of B. bufo in Asia approximately corresponds to the latitude 63-64° N.
Further studies of the species distribution at its northern limit, and
especially in its eastern part, are necessary. Southern margin of the range
in Europe corresponds approximately to the southern limits of the latter. It
is absent, however, from many European islands (Balears, Corsica, Sardinia,
Malta, Crete etc.).
On the continental part, the southern margin runs by the right bank of Dnieper River in Ukraine approximately along the line Kherson City (48° 38'N, 32° 37'E) - area of Zaporozhie City - Dnepropetrovsk Province - Donetsk Province - Kharkov Province - Lugansk Province. Then the margin runs in Russia in the southwest of Byelgorod Province - Voronezh Province - Tambov City (52° 43'N, 41° 26'E) - south-east of Penza Province - Ulyanovsk Province - north of Saratov Province. Then the margin runs to northwestern Kazakhstan: north of Uralsk Province. The toad probably exists on the rivers Uil and Temir southwards to 49° N. Then the margin turns northeastwards in Russia approximately along the line Orenburg Province - Chelyabinsk Province - Kurgan Province - south of Tyumen
Province in the West Siberia - east of Omsk Province. Then the margin turns to the south-south-east at a level of about 55° E to the Northeastern Kazakhstan. Then the margin runs to the south-east
and south along the valley of the Irtysh River to Semipalatinsk Province and the East Kazakhstan Province and then, probably, to China.
Bufo bufo from the Anatolian Turkey area, Syrian Arab Republic, and Lebanon, is referred to the subspecies verrucosisimus (formerly a separate species) by Recuero et al 2012. The subspecies Bufo bufo verrucosisimus or Caucasian Toad differs by its larger size (ranging from 70-190 mm snout-vent lenght), body proportions, tongue shape, skin texture and coloration and more pronounced sexual dimorphism in body size. In the Caucasian toad, males do not have a resonator, or a tarsal fold. In addition, the Caucasian toad has 2nd and 3rd toes with paired subarticular tubercles. The dorsal skin contains large rounded tubercles, and the ventral skin has small tubercles. The dorsal surface is gray or light-brown, with dark spots. Longitudinal stripes, more or less developed, are present on parotoids. The belly is gray or yellowish. The male differs from female by a considerably smaller body size and other characters similar to those involved in the sexual dimorphism of B. bufo. However, there is no sexual dimorphism in coloration. (Tarkhnishvili and Gokhelashvili 1999).
The Common Toad is associated mainly with the forest zone (in conifer,
mixed and deciduous forests), where it prefers conifer forests with
marshes. It lives in groves, bushlands, parks and gardens, generally
in fairly wet sites with dense vegetation. Large open areas are avoided
but in forested landscapes the toad readily inhabits bushlands, meadows,
fields, glades, gardens, vineyards etc. In the south of the range, the toad
lives in insular forests in the zone of forest steppe and in wet and dense
riparian vegetation. Spawning takes place in lakes, ponds, ditches, large
puddles and streams with relatively clear water, quite variable in area and
depth.
Life History, Abundance, Activity, and Special Behaviors
In most habitats, Bufo bufo is not very abundant, although sometimes up to 70 specimens are found per 100 m of pond shore or, on land, to 200 individuals per hectare.
As other toads, B. bufo is active mainly in twilight. The activity in light time, common for the toads of the Bufo viridis group, is rare in the Common Toad. The toads hibernate singly or in groups from September - beginning of November to March - June, depending on the altitude and latitude. Hibernation occurs on land and occasionally in streams and springs. Usually, the hibernation is finished in April - May. Reproduction occurs from March - June (usually late April - May). Amplexus is pectoral. A few males often clasp one female, and in many instances several males try to clasp the same female, and large "balls" consisting of numerous toads may be observed. The smallest males are forced out by larger individuals. Therefore, assortative (by body size) mating takes place. Embryonic and larval development takes usually 1.5-2.5 months.
Common Toad forages exclusively on land, mainly on crawling invertebrates. As in other species of toads, consumption of ants is very typical. This results from the sit-and-wait foraging tactics in this species. Numerous predators, parasites and morphological anomalies are known in this toad species. However, their real impact in its population dynamics remains unknown. If faced by a potential predator, the adult toad lifts its body on straight legs and butts its head toward the danger.
Trends and Threats
Destruction of forests and meadows, as well as artificial drying of wetlands compose the most serious threats for populations of B. bufo . These factors are responsible for the extinction of some populations. On a global scale, deforestation of the European south may have resulted in a retreat of the species' range northwards. Pollution of the environment by mineral fertilizers and industrial wastes, recreation, urbanization, mortality on roads, meaningless killing by people etc. result in the gradual decline of populations of B. bufo in settlements and cities. Natural factors may also influence the abundance and distribution of this species. For example, in Moscow Province in 1990s its abundance gradually increases, and the Common toad appears in places where it was absent in the past.
The UK has designated the species as a Biodiversity Action Plan (BAP) priority species in response to declines in some areas of central and lowland England, and on the Channel Island of Jersey (John W. Wilkinson & John Buckley, FrogLog 2012).
Relation to Humans
Main threats related to human activities were indicated above. Although a few populations of the Common Toad are able to survive even in cities, it has moderate possibilities for synanthropization: the toad is practically extinct from many large cities where many other amphibians are in relatively safe condition.
B. bufo have a tendency to breed in the same location they were born, even if other breeding areas are available nearby. This increases their susceptibility to landscape development by humans (John W. Wilkinson & John Buckley, FrogLog 2012).
Possible reasons for amphibian decline General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Disturbance or death from vehicular traffic
Local pesticides, fertilizers, and pollutants
Long-distance pesticides, toxins, and pollutants
Intentional mortality (over-harvesting, pet trade or collecting)
Comments
This species was featured as News of the Week on 21 February 2022:
How will increasing temperatures from the climate crisis impact amphibian aging and mortality? Despite its relevance to conservation, little data exists on the relationship between temperature and senescence in free-living animals. Cayuela et al. (2021) studied pairs of frogs from two families divided by 100 million years of evolutionary history to answer this: Rana luteiventris and R. temporaria (Ranidae) and Anaxyrus boreas and Bufo bufo (Bufonidae). The North American toads (Bufonidae) represented sampling along a climatic gradient, whereas the ranid frogs represented sampling from climatically contrasted sites. They found that actuarial senescence rates— i.e., the rate at which mortality increases with age— increased with the mean annual temperature experienced in all species. In all species but Anaxyrus boreas, increasing temperatures corresponded to decreasing lifespans. These relationships are presumably attributed to amphibians' increasing pace of life with increasing temperatures; they are active for longer periods, have a higher metabolism, lower mitochondrial efficiency, and accumulate oxidative damage more rapidly. The impacts of increasing temperature on these frogs might be exacerbated by increasing evaporative water loss and influenced by genes involved in adapting amphibians to warmer conditions. In the ranids studied, the authors found increasing temperatures flipped sex differences in senescence rate in R. luteiventris but not R. temporaria. These results paint a grim picture for amphibians as global temperatures increase. Amphibian aging is expected to accelerate, with potential skewing sex ratios in some species. (Written by Emma Steigerwald)
This species was featured as News of the Week on 7 August 2023:
No one likes mosquitos, or the diseases they transmit, but there is a positive link between their abundance and human-caused landscape alterations. Conversely, while amphibian density has been shown to have a negative relationship on mosquitos density, amphibians also are negatively impacted by human modifications to their habitat. Perrin et al. (2023) examined the interaction of these relationships with a survey of 77 anthropized ponds in western Switzerland. While their methods were indirect, their structural equation models and path analyses point to ponds with amphibians having reduced abundance and diversity of mosquitoes, likely through limiting competition and predation by amphibians. Their analysis also found that ponds were more likely to have amphibians if they were deeper and older, as mosquitos often colonize new ponds immediately while it takes a few years for their predators to do so. The authors argue that removing wetlands to reduce mosquito populations is counterproductive as it impacts mosquito predators more than mosquitos, and they encourage the development of more measures to protect amphibians. (Written by Ann Chang)
This species was featured as News of the Week on 14 October 2024:
It’s not unheard of to find male amphibians in amplexus with an inappropriate target. Some more ridiculous examples that the AmphibiaWeb team have seen on the internet or in person included a rotting mango, shoes, and a chain of cane toads grasping a snake. Given the costs of these reproductive mistakes, Soni et al. (2024) investigated the phenomena by creating a dataset of documented misdirected amplexus. Unsurprisingly, more closely related species of similar body size and microhabitat use are more likely to be engaged in misdirected amplexus with each other. However, terrestrial and arboreal species, explosive breeders, and species found in temperate regions also have more documented cases of misdirected amplexus. These findings indicate that evolutionary relatedness, ecological niche, breeding phenology, and geography all play a role in explaining these misdirected mating attempts. And a better understanding of breeding biology can inform our conservation and management efforts, as well as enchant us. (Written by Ann Chang)
References
Baloutch, M. and Kami, H. G. (1995). Amphibians of Iran. Tehran University Publishers, Tehran.
Bannikov, A. G., Darevsky, I. S. and Rustamov, A. K. (1971). Zemnovodnye i Presmykayushchienya SSSR [Amphibians and Reptiles of the USSR]. Izdatelistvo Misl, Moscow.
Bannikov, A. G., Darevsky, I. S., Ishchenko, V. G., Rustamov, A. K., and Szczerbak, N. N. (1977). Opredelitel Zemnovodnykh i Presmykayushchikhsya Fauny SSSR [Guide to Amphibians and Reptiles of the USSR Fauna]. Prosveshchenie, Moscow.
Basoglu, M. and Ozeti, N. (1973). Turkiye Amphibileri. Ege Univ, Bornova-Izmir.
Gasc, J. P. , Cabela, A., Crnobrnja-Isailovic, J., Dolmen, D., Grossenbacher,K., Haffner, P., Lescure, J., Martens, H., Martinez Rica, J. P.,Maurin, H., Oliveira, M. E., Sofianidou, T. S., Vaith, M., and Zuiderwijk, A. (1997). Atlas of Amphibians and Reptiles in Europe. Societas Europaea Herpetologica and Muséum National d’Histoire Naturelle, Paris.
Hraoui-Bloquet, S., Sadek, R. and Geze, R. (2001). ''Les Amphibiens du Liban: inventaire, répartition géographique et altitudinale.'' Bulletin de la Société Herpétologique de France, 99, 19-28.
Kuzmin, S. L. (1995). Die Amphibien Russlands und angrenzender Gebiete. Westarp Wissenschaften, Magdeburg.
Kuzmin, S. L. (1999). The Amphibians of the Former Soviet Union. Pensoft, Sofia-Moscow.
Nikolsky, A. M (1936). Fauna of Russia and Adjacent Countries: Amphibians (English translation of Nikolsky, 1918, Faune de la Russie et des Pays limitrophes. Amphibiens. Académie Russe des Sciences, Petrograd, USSR). Israel Program for Scientific Translations, Jerusalem.
Nikolsky, A. M. (1906). Herpetologia Rossica. Mémoires de l'Académie Impériale des Sciences de St.-Pétersbourg, Série 8, Phys.-Math, Vol. 17, Sofia, Moscow.
Nöllert, A. and Nöllert, C. (1992). Die Amphibien Europas. Franckh-Kosmos Verlags-GmbH and Company, Stuttgart.
Recuero E, Canestrelli D, Vörös J, Szabó K, Poyarkov NA, Arntzen JW, Crnobrnja-Isailovic J, Kidov AA, Cogălniceanu D, Caputo FP, Nascetti G, Martínez-Solano I (2012). ''Multilocus species tree analyses resolve the radiation of the widespread Bufo bufo species group (Anura, Bufonidae).'' Molecular Phylogenetics and Evolution, 62(1), 71-86. [link]
Ryzhikov, K. M., Sharpilo, V. P. and Shevchenko, N. N. (1980). Gelminty Amfibii Fauny SSSR [Helminths of Amphibians of the USSR Fauna]. Nauka, Moscow.
Szczerbak, N. N. and Szczerban, M. I. (1980). Zemnovodnye i Presmykayushchiesya Ukrainskikh Karpat [Amphibians and Reptiles of Ukrainian Carpathians]. Naukova Dumka, Kiev.
Terent'ev, P. V. and Chernov, S. A (1965). Key to Amphibians and Reptiles [of the USSR]. Israel Program for Scientific Translations, Jerusalem.
Originally submitted by: Sergius L. Kuzmin, John Cavagnaro (first posted 1999-09-30)
Edited by: Vance T. Vredenburg, Kellie Whittaker, Michelle S. Koo (2024-10-13)Species Account Citation: AmphibiaWeb 2024 Bufo bufo: Common Toad <https://amphibiaweb.org/species/127> University of California, Berkeley, CA, USA. Accessed Dec 18, 2024.
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Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 18 Dec 2024.
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