© 2016 Dr. Joachim Nerz (1 of 91)
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Albania, Austria, Belarus, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, Estonia, France, Germany, Greece, Hungary, Italy, Kazakhstan, Latvia, Lithuania, Moldova, Republic of, Montenegro, Poland, Romania, Russian Federation, Serbia, Slovakia, Slovenia, Spain, Switzerland, Ukraine
Bufo viridis is one of the most polytopic amphibians of the Palearctic. It lives in the zones of forests, forest steppes, steppes, semi-deserts and deserts. It is more tolerant to dry conditions than many other amphibians. It inhabits both wet swampy areas as well as dry deserts of different types. In the forest zone, the species tends to live in open areas and bushlands, often far away from water bodies, whereas in the southern dry parts of the range it primarily inhabits moist sites such as oases, the shores of irrigation ditches and lakes. There it uses irrigation ditches and channels as corridors for dispersal. Spawning occurs in a diverse range of water bodies including ponds, swamps, lakes, stream- and river pools, reservoirs, ditches and puddles, as a rule not deeper than 50 cm. Both fresh and saline waters are used for spawning.
Life History, Abundance, Activity, and Special Behaviors
Green toads are very heat-tolerant amphibians: the upper temperature limit appears to be near +40oC. They are also quite tolerant to desiccation (the death occurs when the body loses ca. 50% of its water). In dry areas, the toads regularly visit water bodies at night to rehydrate. Green Toad is active mainly in the twilight and at night and spends the daytime in hiding places. During reproduction, toads are active in daytime. Even terrestrial adults are often active on sunny days and in open areas. Daylight activity is known primarily from the southern dry part of the range and in the highlands. On hot days, the toads frequently stay in shallow water. On the other hand, migrations of long distances, up to 2-5 km from the breeding ponds are typical.
Hibernation occurs on land, but sometimes it occurs in water such as streams, ditches and wells. Toads hibernate singly or in groups. The timing of hibernation varies significantly through the range, in dependence on altitude and latitude. In southern parts of distribution, the hibernation often is absent, and the toads are active throughout the year. On the other hand, in southern deserts, aestivation supposedly occurs. Reproductive period is also quite variable, from February to July in different parts of the range. In the southern areas, the reproductive period is the longest (ca. 170 days), whereas the duration of development prior to metamorphosis is shortest (ca. 21-25 days).
Spawning occurs in a diverse range of water bodies including ponds, swamps, lakes, stream- and river pools, reservoirs, ditches and puddles, as a rule not deeper than 50 cm. Both fresh and saline waters are used for spawning.The Green Toad uses two mating strategies: active female choice by the competing males and active male choice by the females. Amplexus is pectoral. Assortative mating has been recorded. The clutch contains 2000-30000 eggs arranged in 1-2 rows. The spawn is deposited in two strings of 2-7 m length. Metamorphosis occurs from spring through the summer, in dependence on the latitude and altitude. Mass appearance of newly metamorphosed juveniles is typical for the Green Toad. In such cases pond shores may be covered with thousands of toadlets which disperse from the pond soon after their metamorphosis. Sometimes migrating toadlets form large groups moving as a large band. Maximum longevity is estimated at 7-10 years in different populations of the Caucasus.
Tadpoles consume detritus and algae and move towards the shore in daytime and to greater depths in the evening. Animals (Protozoa, Rotatoria, Microcrustacea) are consumed in smaller amounts. Newly metamorphosed toadlets prey upon Collembola, Coleoptera, Acarina and Diptera. Adults eat mainly crawling invertebrates, including spiders, beetles etc. Small amounts of aquatic invertebrates sometimes occur in stomachs of individuals caught in the spring along pond shores. However, the majority of toads do not feed during their breeding migrations. In similarity to other toad species, the Green Toad displays mirmecophagy. Ants compose a significant component of the adult but not juvenile food. Therefore, this peculiarity develops in the toad's postmetamorphic life and may relate to age changes in its foraging strategy.
The Green Toad composes an important component of food in many predatory vertebrates. Some snakes (e.g., Naja oxiana) prefer toads to frogs (Rana spp.).
Trends and Threats
Relation to Humans
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Written by Sergius L. Kuzmin (ipe51 AT yahoo.com), Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow
First submitted 1999-09-30
Edited by Vance Vredenburg; JG (fixing maps 7/25/01) (2001-07-24)
Species Account Citation: AmphibiaWeb 2001 Bufotes viridis: Green Toad <http://amphibiaweb.org/species/312> University of California, Berkeley, CA, USA. Accessed Sep 17, 2019.
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Citation: AmphibiaWeb. 2019. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 17 Sep 2019.
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