Common Toad

Nomenclature

Common name:  Common toad   /SARG/13000-Identification/Anuran_Negative.jpg
Taxonomy:  Bufo bufo (Linnaeus, 1758)
Other Names:   Jeriais (Jersey)
Crapaud (Jersey)

Introduction

/SARG/08000-TheAnimals/SpeciesPages/Common_Toad/Common_Toad_Portrait.jpg
The Common toad may be identified by its warty skin and protruding paratoid glands.

The Common toad has a dry warty skin, large warty glands behind the eyes, short legs, a round blunt snout, a pale spotty belly and golden/bronze eyes. They can vary in colour from dark brown to brick red.

Common toads can be found in deciduous/mixed woodlands, hedgerows, scrub, some gardens, rough grassland (particularly wet meadows) and wetlands.

This toad is classed worldwide as a species of Least Concern, Although, it is considered to be Near Threatened in Spain because of recent declines due to habitat loss, as well as progressive aridity. In Britain it is widespread, however, populations have declined and it is now listed as a Priority Species of Conservation Concern.

The Common toad is widespread in the UK, although it appears to be uncommon in northern Scotland. The Common toad is found on the Channel Islands of Jersey, where it is called the Crapaud or Jeriais. It is native to the island, and grows larger than mainland Common toads. It has been introduced to Guernsey. The Common toad is absent from Northern Ireland and the Isle of Man.

As a defence mechanism, the Common toad can secrete toxins through its glandular skin if attacked by a predator.


Identification

/SARG/08000-TheAnimals/SpeciesPages/Common_Toad/Toad2.jpg

The main unique ID feature is the toad’s skin, which is dry and warty unlike that of a frog which is smooth and usually moist. Common toads have distinctive large glands behind the eyes called Paratoid glands, which like all glands in the toad skin can secrete toxins if a toad is attacked by a predator. The Common toad is squat and has a blunt rounded snout and head, unlike a frog’s head and snout which is pointed. The legs of a Common toad are short and the animal uses a mix of crawling and hopping to move, unlike a frog which has longer legs for jumping. The eyes of a Common toad are a golden bronze colour and the pupils are horizontal, unlike that of a frog whose pupils are more round or oval. Common toads don’t have the distinctive dark face mask that is possessed by the Common frog.

Common toads can vary in colour from earthy browns and greys through to brick red in some areas (particularly if the local soil is reddish/brown with iron oxides). The underside is pale cream with spots and speckles.

Male Common toads are generally smaller than females and can measure up to 6cm, whereas females can measure up to 9cm. During the breeding season, dark nuptial pads can be found on the male’s inner three fingers, whereas a female has no nuptial pads. If picked up a male will squeak, whereas a female will not.

Apart from the Common frog which is often encountered, the other British amphibians that Common toads may be mistaken for are the Water frogs (Marsh, Edible, Pool and their hybrids), and the Natterjack toad. Water frogs as their name suggests are generally found in or next to water (All through the active season), are green/brown often with a pale/yellow stripe along the back, and have a streamlined head with pointed snout. The Natterjack toad is smaller than the Common toad, and due to its rarity and specific habitat requirements (Heathland, coastal dunes and marshes) is not often encountered. Natterjack toads have a distinctive yellow stripe along the back, and due to their short legs are adapted to running across and burrowing into sand/sandy soils.


Distribution

The Common toad is widespread in Europe (excluding most Mediterranean islands (though it is present on Sicily), and northern Eurasia, with populations in parts of West Asia (Turkey, Syrian Arab Republic and Lebanon) and north Africa (Morocco, Algeria and Tunisia). The Common toad is absent from Ireland. In Europe, it is present in most areas (including Norway, Sweden and Finland), ranging as far eastwards as northern Kazakhstan and eastern Siberia. In the Middle East, it is found through much of Turkey, north western Syrian Arab Republic, and has recently been recorded from two mountainous locations in Lebanon. In Africa it has a very fragmented range in the more mountainous regions. The species has an altitudinal range of sea level to 3,000m. There are two sub-species of Common toad within Europe; Bufo bufo spinosus, found in southern Europe and along the Mediterranean coast; and Bufo bufo gredosicola, found in the Sierra de Gredos region of central Spain.

The Common toad is widespread in the UK, although it appears to be uncommon in northern Scotland. The Common toad is found on the Channel Islands of Jersey (where it is native, grows larger than mainland Common toads and is known as the Crapaud or Jeriais), and Guernsey (where it was introduced). The Common toad is also absent from Northern Ireland and the Isle of Man.

The Common toad is widespread in Surrey however, populations appear to be declining.

National distribution

National distribution for the Common Toad

Surrey distribution for the Common Toad


Habitat

The habitat preferences are unimproved (rough) grassland, scrub and open woodland (usually deciduous/mixed). These areas should be close to large, permanent water bodies (Optimum pond size is 1,000 square metres) with a good cover of emergent and sub-emergent vegetation for breeding purposes. Toads do use gardens (Particularly those with rough areas and compost heaps), but many garden ponds are too small or competition from the larger tadpoles of the Common frog too high for toads to breed successfully.

Common toads are generally active on mild, damp nights, and shelter during the day under cover (logs, fallen bark or even broken plant pots) or buried in leaf litter. Common toads hibernate in frost free hollows or holes often in woodland or at the bases of hedgerows/scrub.


Activity

Common toads are predominantly nocturnal; however some individuals on rare occasions can be active during the day (depending on local weather conditions and the animal’s health status).

Common toads generally hibernate from late October until early March (although some may be active in late February, depending on local weather conditions). Upon emerging from hibernation toads start to migrate back to their breeding ponds.

Males emerge first at dusk and await the females. Males will often clasp the larger females, using their nuptial pads, on route to the ponds. Once in the pond males will occasionally call to attract females, but generally rely on fighting to secure mates.

After mating the females will lay strings of double stranded eggs and wrap them around aquatic vegetation. Tadpoles hatch from the eggs 10 – 14 days later and after a few days, cluster together in shoals. The tadpoles usually take between 8 and 12 weeks to complete development and emerge as toadlets during August.

January


  • Most animals in hibernation

February


  • First emergence from hibernation
  • Courtship
  • Egg-laying
  • Toad crossings
  • Torchlight survey

March


  • Aquatic adults
  • Courtship
  • Egg-laying
  • Tadpoles
  • Torchlight survey

April


  • Aquatic adults
  • Courtship
  • Egg-laying
  • Tadpoles
  • Torchlight survey
  • Some terrestrial adults

May


  • Terrestrial adults
  • Tadpoles
  • Early metamorphosis

June


  • Terrestrial adults
  • Tadpoles
  • Late metamorphosis

July


  • Terrestrial adults and juveniles

August


  • Terrestrial adults and juveniles

September


  • Terrestrial adults and juveniles

October


  • Terrestrial adults and juveniles

November


  • Most animals in hibernation

December


  • Hibernation

Food

Adult toads will feed on a variety of invertebrates, molluscs, earthworms and even their own young!. They are sit and wait predators and respond to movement. They are known to wander around gardens and snap up passing invertebrates using sticky pads on their tongues. Adult toads generally will not feed until breeding has finished. Toadlets feed on smaller invertebrates, such as aphids.

Tadpoles feed on microorganisms, such as algae and rotifers.

Invertebrates such as the wood louse.
Invertebrates such as the wood louse.
Earthworm.
Earthworm.
Slug.
Slug.

Predators

Toads suffer from fewer predators than frogs, as they produce a foul-tasting toxin (bufagin) within their skin. This toxin occurs in adults, toadlets and tadpoles. Even with this defence, adult toads are predated by a variety of animals including birds, mammals and snakes. The tadpoles are additionally predated by newts and predatory insects.

Avian threats come in the form of herons, corvids and raptors. The grass snake is a major predator of the common toad, and juvenile snakes are known to be ravenous feeders of toad tadpoles.

Mammalian threats include mink, hedgehogs and brown rats. Domestic cats also occasionally kill toads.

When threatened by a predator, Toads will assume a defensive posture; inflating their bodies and raising themselves on their toes in an attempt to look as large as possible. Recent research has shown that in some areas, crows have become adept at predating toads by pecking through the toxic skin and removing the nutritious liver. In doing this, the toad's diaphram is punctured, so when the toad does inflate, it has no means of controlling the inflation. This combination kills the toad, and it can often seem that numerous toads have 'exploaded' in a seemingly mass mortality incident.

Tadpoles exude sufficient toxins to deter predators such as most fish, and our smaller newt species; however, the Great crested newt feeds heavily upon toad tadpoles, probably swallowing the tadpole before any foul taste is detected. Similarly, predatory insects such as dragonfly nymphs, diving beetles (adults & larvae) and Greater water boatmen tend to pierce the tadpole's skin, sucking out its vital juices, avoiding the skin toxins altogether.

Toad tadpoles are known to shoal, like fish, in order to confuse predators.

Defensive posture ©Lukasz Olszewski
Defensive posture ©Lukasz Olszewski
This crow could have taken this toad as carrion although they will predate living toads.
This crow could have taken this toad as carrion although they will predate living toads.

Shelter

/SARG/08000-TheAnimals/SpeciesPages/Common_Toad/Common_Toad_Hole.jpg
Toads dig a small recess under refugia, such as stones for daytime shelter.

For hibernation sites, they use log piles, compost heaps and stone walls.

Toads are nocturnal creatures, and will spend the day hidden away in damp and sheltered locations which offer good feeding opportunities. They typically excavate a small hollow in the ground, beneath a stone, piece of wood or even a flower-pot. Gaps in old walls and deep leaf-litter are favourite haunts.


Reproduction

/SARG/08000-TheAnimals/SpeciesPages/Common_Toad/Common_Toad_Piggyback.jpg
The smaller male toad will often grab a passing female and get a lift to the breeding pond.

Upon emerging from hibernation toads start to migrate back to their breeding ponds. Males emerge first at dusk and await the females. Males will often clasp the larger females, using their nuptial pads, on route to the ponds. Once in the pond males will occasionally call to attract females, but generally rely on fighting to secure mates.

If a male is clasped by another male by mistake, then he will emit a small croak and kick until the other male lets go. If a male emits a deeper croak then the attacking male can assess the fitness of the defending male, and will generally back off if the attacking male is smaller. Females generally stay silent, although they do emit a ‘release call’ if a male toad clasps them after they have deposited their eggs.

Other males will often try to dislodge males in amplexus, and can form ‘toad balls’ as many males try to dislodge other males and mate with the female. This can lead to the female drowning. This behaviour is caused by an uneven sex ratio of more males than females.

Once a female is ready to lay her eggs, she will hunch her back in order to bring her cloaca closer to the males. Two strings of double-stranded eggs are extruded simultaneously and are fertilised by the males sperm. The pair move through aquatic vegetation in which the toad spawn becomes attached. Common toads often spawn in deeper water than that of Common frogs. In the UK, female Common toads produce between 400 and 5,000 eggs.

Common toad spawn is laid as a pair of strings.
Common toad spawn is laid as a pair of strings.
Toad spawn (left) compared to Frog spawn (right).
Toad spawn (left) compared to Frog spawn (right).

Juveniles

Tadpoles hatch from the eggs 10 – 14 days later and after a few days, cluster together in shoals. The tadpoles usually take between 8 and 12 weeks to complete development and emerge as toadlets during August. Common toad tadpoles are black and generally smaller than those of Common frogs.

Toadlets are miniature versions of the adults and will hide in moist places away from potential predators and feeding on small invertebrates, such as aphids.


Conservation

Although the Common toad is a widespread species in Britain, populations have declined and it is now listed as a Priority Species in the UK Biodiversity Action Plan.

The main conservation threats to Common toads are habitat loss (both for breeding sites and hibernation sites), pollution, heavy road mortality on breeding migrations and diseases such as Chytrid (See links).

Links

Designation Applicability
Species of conservation concern:   Yes (Priority species)
CITES (1975):   No
Bonn Convention (1979):   No
Wildlife & Countryside act (1981) Section 9.1 (Kill/Harm/Take):   No
Wildlife & Countryside act (1981) Section 9.4 (Damage/Disturb shelter):   No
Wildlife & Countryside act (1981) Section 9.5 (Sale):   Yes
Bern Convention (1982):   No
Conservation Regulations (1994/2007):   No
EC Habitats & Species Directive:   No
IUCN Red List:   Not Listed

Information

Principal Author: Main Illustrator: Review: Updated:
Danial Winchester Steve Langham Reviewer 24 Mar 2008