Mr Toad on his annual march
Each February, masses of amphibians make their way to a familiar pond for the breeding season
IT IS AN hour or so after dusk on a mild, damp February evening. From beneath a log pile at the bottom of a garden, a Common toad emerges. Tonight, it will make the journey back to the pond in which it will hopefully breed. Soon, it is joined by a second toad, followed by a few more, those numbers increasing until a veritable army of toads is on the march. If they manage to survive the threats of predators and motor vehicles on their route, the toads should reach their destination within a few hours, remaining there for the spring and summer.
The Common toad, Bufo bufo, and the Common frog, Rana temporaria, are approximately the same size, at between 2½-4in (6-10cm) in length. Superficially, they are also similar in shape and appearance. But a closer look reveals that toads have a less smooth skin, sometimes referred to as ‘warty’, with small, raised lumps, and an overall ‘drier’ and less moist sheen. They are also more uniform in colour than the Common frog, being a brown or greyish-brown shade and lacking the frog’s green coloration, while their underparts are whitish, with darker blotches, unlike the off-white colour of the frog; the flanks are slightly greyer or greener in the male toad than the browner female. Young toads, and occasionally adult females, can appear more rufous in colour. Females are, on average, slightly larger than males.
Toads have a plainer, blunter face; that of a frog is more pointed, with an obvious dark patch behind the eye. Another obvious identification feature to look for is the eyes. Those of the toad are golden- or copper-coloured, rather than black.
“I cannot tell by what logic we call a toad, a bear, or an elephant ugly; they being created in those outward shapes and figures which best express the actions of their inward forms”
Structurally, too, there are differences: toads are more compact, with shorter legs, because they crawl, rather than hop or jump in the way that frogs do.
In terms of where they choose to live, Common toads are very adaptable. Unlike frogs, although they like damp conditions, they are often found well away from water. They can make their home in a wide range of habitats, including mixed and broad-leaved woodland, scrub, moorland, heathland, the edges of fields, and parks and gardens, especially those with lakes or ponds. In Britain, they can be found in upland as well as lowland areas, while in southern Europe, they may live at altitudes of 8,200ft (2,499m) above sea level.
Toads are well camouflaged, as their warty skin enables them to blend into most backgrounds. They are also more nocturnal than frogs and are rarely seen during the day unless they are disturbed, apart from when mating, when they may be very conspicuous.
From October through to February or March, toads are solitary animals and hibernate in log piles, burrows under hedgerows or deep inside the leaf litter in woods. Having emerged on the less cold nights in late winter, they make their way to their breeding territories in ponds and other watery places, often using the same pond year after year. Unlike frogs and newts, toads can live and breed successfully in ponds alongside fish: the tadpoles of toads are poisonous to fish, and so escape being eaten.
When returning to their breeding areas, they find their way using a range of cues, including the Earth’s magnetic field, the light of the moon and their acute sense of smell. However, this is a dangerous time: many are run over and killed by cars or caught by predators. In recent years, local wildlife groups have run ‘toad patrols’ to ensure that the animals are safe, even picking them up and taking them to be released into a suitable pond.
Males return to their breeding areas first, sometimes as much as three weeks before the females, and stay there for much longer. Once the females finally arrive, usually in March or April, mating begins. The male attracts the female by croaking and sometimes by fighting off his rivals; he then grabs her in a tight grip, known as ‘amplexus’, using special sucker pads on
his forelimbs to increase his grip. He often holds onto her for hours while she gradually releases her eggs, which he fertilises as they leave her body.
Unlike frogs’ eggs, which are laid in rounded clumps, the eggs of a toad are produced in a string, up to 14½ft (4.4m) long and containing as many as 6,000 eggs. Up to four out of five males do not get the chance to mate at all and may, in their frustration, clamber onto the backs of mating couples, drowning them in the process. Once breeding is over, the female heads elsewhere for the rest of the year.
Growing and changing
Once the eggs are fertilised, they remain in the pond for another 10 days until the tadpoles hatch out. Over the next two to three months, the tadpoles develop, growing to approximately 1¼in (3cm) long. During this period, the vast majority are eaten by aquatic creatures, such as water boatmen, diving beetles and dragonfly nymphs.
Eventually, the tadpoles acquire all four limbs and lose their tail. At this point, they are known as toadlets and may measure less than ½in (1.3cm) in length. They will remain in the pond, feeding on tiny insects, such as aphids and crickets, and growing until they leave in August; approximately four months after they first hatched out as tadpoles. They will reach full maturity after three or more years.
Adult toads feed on a wide range of insects and other invertebrates, including spiders, earthworms, caterpillars, ants, woodlice and slugs. They hunt by stealth, creeping up on their prey, then extending their sticky tongue to catch their victim. They may also predate on baby grass snakes, harvest mice and sometimes even smaller toads. Having no teeth, they simply swallow their food whole.
Toads secrete toxins through their skin: a specific poison known as bufotoxin, which can cause serious irritation to human eyes and skin. As a result, they are generally avoided by predators. However, herons, grass snakes and various members of the crow family will catch and feed on