european toad (Pyrenees' Biodiversity)

european toad

Bufo bufo

Summary ⁶

The common toad, European toad or in Anglophone parts of Europe, simply the toad (Bufo bufo, from Latin bufo "toad"), is an amphibian found throughout most of Europe (with the exception of Ireland, Iceland, and some Mediterranean islands), in the western part of North Asia, and in a small portion of Northwest Africa. It is one of a group of closely related animals that are descended from a common ancestral line of toads and which form...

Biology ⁷

Common toads are largely nocturnal. They are found in ponds only in the breeding season; during the rest of the year they can be found far from water bodies (5). They have a broad diet, feeding on a huge range of prey small enough to swallow, including insects, spiders, earwigs, earthworms, snails and slugs; they have even been observed eating young toads (2). They feed only on land and use a 'sit-and-wait' style of hunting (6). Toads are usually welcomed by gardeners, thanks to their voracious appetites and penchant for garden pests (4). The life cycle is similar to that of the common frog (Rana temporaria). Common toads begin to migrate to breeding ponds in autumn. The onset of cold weather stimulates hibernation, which takes place en route in abandoned rodent burrows or in leaf litter (2). Migration then recommences in spring. Breeding activity, which occurs between March and June (6), is often very frenzied in this species, with much competition amongst males over access to females. Males grasp females tightly prior to spawning, and there is aggressive activity amongst males who try to 'take-over' females. 'Mating-balls' may often arise, when as many as 10 males jostle for access to a single female; the female occasionally drowns or is crushed as a result (2). Successful pairs will spawn; females release a double-string of eggs, which the male fertilises by releasing his sperm simultaneously. The pair moves around whilst spawning, so that the jelly-coated strings of eggs become wrapped around vegetation. One female may produce up to 5,000 eggs, although the usual number is around 1,500 (2). The black tadpoles move away from the spawning areas a few days after hatching. The tadpoles feed on microorganisms and usually gather in groups, which, in addition to the presence of skin toxins, probably protects them further against predation. Despite this, however, they frequently become prey for diving beetles and other species that have piercing mouthparts, and so can avoid the toxins in the skin (2). It takes 8-12 weeks for tadpoles to develop, after metamorphosis the tiny toadlets occasionally emerge en masse. Sexual maturity is reached after 2-3 years (2). Common toads can live for a very long time; some captive individuals have reached 50 years of age (5).