American toad

American toad

Overview
The American Toad is a common species of toad
Toad
A toad is any of a number of species of amphibians in the order Anura characterized by dry, leathery skin , short legs, and snoat-like parotoid glands...

 found throughout the eastern United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 and Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

. It is divided into three subspecies—the Eastern American Toad (B. a. americanus), the Dwarf American Toad (B. a. charlesmithi), and the rare Hudson Bay Toad (B. a. copei). Newer taxonomies consider this species Anaxyrus americanus
Anaxyrus
Anaxyrus is a subgenus of true toads, genus Bufo, native to North and Central America. Some authors have recognized Anaxyrus as a separate genus, but this makes the rest of Bufo paraphyletic .-Species:-References: The history of a Nearctic...

.

The eggs of the American Toad are laid in two strings and can hatch in 3–13 days.
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Encyclopedia
The American Toad is a common species of toad
Toad
A toad is any of a number of species of amphibians in the order Anura characterized by dry, leathery skin , short legs, and snoat-like parotoid glands...

 found throughout the eastern United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 and Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

. It is divided into three subspecies—the Eastern American Toad (B. a. americanus), the Dwarf American Toad (B. a. charlesmithi), and the rare Hudson Bay Toad (B. a. copei). Newer taxonomies consider this species Anaxyrus americanus
Anaxyrus
Anaxyrus is a subgenus of true toads, genus Bufo, native to North and Central America. Some authors have recognized Anaxyrus as a separate genus, but this makes the rest of Bufo paraphyletic .-Species:-References: The history of a Nearctic...

.

Tadpoles


The eggs of the American Toad are laid in two strings and can hatch in 3–13 days. When hatched the tadpole
Tadpole
A tadpole or polliwog is the wholly aquatic larval stage in the life cycle of an amphibian, particularly that of a frog or toad.- Appellation :...

s are recognizable by their skinny tails in relation to the size of their bodies. They may advance to adulthood in 30–40 days. When metamorphosis is completed, the "toadlets" may stay in the water for a short period of time before they become mostly land based. A mutualistic relationship with Chlorogonium
Chlorogonium
In taxonomy, Chlorogonium is a genus of algae, specifically of the Haematococcaceae. This alga has a notable mutualistic relationship with the American Toad, allowing the tadpoles to develop faster when covered with Chlorogonium....

 alga, which makes the tadpoles develop faster than normal, has been studied.

Tadpoles have several mechanisms to reduce predation. They avoid predators by swimming in very shallow water, and by swimming close together in schools during the day. Tadpoles also produce toxic chemicals in their skin that discourage some potential predators. Fish have been reported to die after consuming one tadpole; however, most fish quickly learn to avoid eating American Toad tadpoles. The tadpoles are also very small and they are a solid black colour.

Subspecies


Races tend to hybridize with Bufo woodhousii
Bufo woodhousii
The Woodhouse's Toad, is a medium-sized true toad, which is native to the United States and Mexico. There are two recognized subspecies. The epithet woodhousii is in honor of the American physician and naturalist Samuel Washington Woodhouse. B...

in their overlapping ranges.

Eastern American Toad


The Eastern American Toad (B. a. americanus) is a medium-sized toad usually ranging in size from 5–9 cm (2–3.5 in); record 11.1 centimetres (4.4 in). The colour and pattern is somewhat variable. Skin colour can change depending on humidity, stress, and temperature. Colour changes range from yellow to brown to black. Their breeding habits are very similar to Bufo fowleri
Bufo fowleri
Fowler's Toad is a species of toad in the Bufonidae family found in North America. It was previously considered a subspecies of Woodhouse's Toad.-Physical Description:...

. The call or voice of a breeding male is a high trill, lasting 6–30 seconds, similar to a ringing telephone. They hibernate during the winter. The Eastern American Toad has spots that contain only one to two warts. It also has enlarged warts on the tibia or lower leg below the knee. While the belly is usually spotted, it is generally more so on the forward half (in some rare individuals there may be few or no spots). This subspecies of the American Toad has no or very little markings on it. The spades on the back legs are blackish. Some toads of this subspecies have red warts on their bodies. Also Eastern American Toads have parotoid glands that are the same colour as the surrounding skin. The glands don't have any patterning on them.
Other species which may be confused with the Eastern American Toad are Fowler's Toad, which has three or more warts in the largest dark spots, and in the far west of its range Woodhouse's Toad. Fowler's Toad can be especially difficult to identify in comparison to the Eastern American Toad but one difference is that it never has a spotted belly and both cranial crests touch the parotoid gland
Parotoid gland
The parotoid gland is an external skin gland on the back, neck, and shoulder of toads and some frogs and salamanders. It secretes a milky alkaloid substance to deter predators...

s. In the Eastern American Toad these crests almost never touch the parotoid glands, which secrete bufotoxin
Bufotoxin
Bufotoxins are a family of toxic substances found in the parotoid glands, skin and venom of many toads ; other amphibians; and some plants and mushrooms. The exact composition varies greatly with the specific source of the toxin. It can contain: 5-MeO-DMT, bufagins, bufotalin, bufotenine,...

, a poisonous substance. The poison the toad excretes is mild in comparison to other poisonous toads and frogs, but it can irritate human skin and is dangerous to smaller animals (such as dogs) when ingested.

American Toads require a semi-permanent freshwater pond or pool with shallow water in which to breed and for their early development. They also require dense patches of vegetation, for cover and hunting grounds. Given these two things and a supply of insects for food, American Toads can live almost everywhere, ranging from forests to flat grassland. Adult toads are usually nocturnal, although juveniles are often spotted in daytime in forested areas. These toads commonly seek cover in burrows, under boardwalks, flat stones, boards, logs, wood piles, or other cover. They are usually easy to find, and their gentle nature makes them good pets. When cold weather comes, these toads dig backwards and bury themselves in the dirt of their summer homes, or they may choose another site in which to hibernate
Hibernation
Hibernation is a state of inactivity and metabolic depression in animals, characterized by lower body temperature, slower breathing, and lower metabolic rate. Hibernating animals conserve food, especially during winter when food supplies are limited, tapping energy reserves, body fat, at a slow rate...

. Their diet includes crickets
Cricket (insect)
Crickets, family Gryllidae , are insects somewhat related to grasshoppers, and more closely related to katydids or bush crickets . They have somewhat flattened bodies and long antennae. There are about 900 species of crickets...

, mealworm
Mealworm
Mealworms are the larval form of the mealworm beetle, Tenebrio molitor, a species of darkling beetle. Like all holometabolic insects, they go through four life stages: egg, larva, pupa, and adult...

s, earthworm
Earthworm
Earthworm is the common name for the largest members of Oligochaeta in the phylum Annelida. In classical systems they were placed in the order Opisthopora, on the basis of the male pores opening posterior to the female pores, even though the internal male segments are anterior to the female...

s, ant
Ant
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...

s, spider
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...

s, slug
Slug
Slug is a common name that is normally applied to any gastropod mollusc that lacks a shell, has a very reduced shell, or has a small internal shell...

s, centipede
Centipede
Centipedes are arthropods belonging to the class Chilopoda of the subphylum Myriapoda. They are elongated metameric animals with one pair of legs per body segment. Despite the name, centipedes can have a varying number of legs from under 20 to over 300. Centipedes have an odd number of pairs of...

s, moth
Moth
A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...

s, and other small invertebrates.

The Eastern American Toad may be confused with the Canadian Toad
Canadian Toad
The Canadian Toad is a species of toad that ranges from the prairie regions of central Canada south to parts of United States upper midwest. Its name is derived from the Latin words bufonis, meaning toad, and hemiophrys, meaning eyebrow, which refers to its pronounced cranial crest between and...

 in the area where they overlap, but the cranial crests in the American Toad do not join to form a raised "boss" (bump) like they do in the Canadian Toad. Its range also overlaps with the Southern Toad
Southern Toad
The Southern Toad is a medium-sized true toad native to the southeastern United States, from eastern Louisiana to southeastern North Carolina. It is most common in areas with sandy soil. Its coloring is usually brown but can be red, gray, or black...

's, but in this species the cranial crests form two unique knobs.

Dwarf American Toad



The Dwarf American Toad (B. a. charlesmithi), is a smaller version of the American Toad which reaches lengths of about 6 cm (2½ inches) and is generally a dark reddish color ranging to light red in some specimens in isolated populations. The spots on the back are reduced or absent, and when present they contain a few small red warts and a black ring around it like in the normal American Toad. The warts are always darker than the skin of the toad. Some specimens have a white dorsal line in the middle of their backs. The ventral surface or belly is usually cream colored with a few dark spots in the breast area. This subspecies can be distinguished from the above mentioned species in the same manner as for the Eastern American Toad. The southwestern portion of the Dwarf American Toad's range overlaps with that of the Gulf Coast Toad
Bufo nebulifer
Bufo nebulifer is a species of toad in the Bufonidae family.It is found in Mexico and the United States.Its natural habitats are temperate forests, temperate grassland, intermittent rivers, swamps, freshwater marshes, intermittent freshwater marches, sandy shores, urban areas, and canals and ditches...

. The latter species is distinguished by the presence of a dark lateral stripe as well as a deep "valley" between its prominent cranial crests. It eats mainly spiders, worms and small insects. This subspecies of the American Toad has been seen in the northern parts of Ontario were there are a few isolated populations. Interbreeding with the normal and eastern American Toads caused this subspecies to lose the red coloring on their backs. These northern dwarf toads mostly have the red coloring on the sides of their bodies and have an unusually high number of warts for the subspecies.

Hudson Bay Toad


The Hudson Bay Toad (B. a. copei) is a rare Canadian subspecies of B. americanus.

External links



  • B. americanus at the United States Geological Survey
    United States Geological Survey
    The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...

     site
  • B. americanus at the USDA
    United States Department of Agriculture
    The United States Department of Agriculture is the United States federal executive department responsible for developing and executing U.S. federal government policy on farming, agriculture, and food...

    's Integrated Taxonomic Information System
    Integrated Taxonomic Information System
    The Integrated Taxonomic Information System is a partnership designed to provide consistent and reliable information on the taxonomy of biological species. ITIS was originally formed in 1996 as an interagency group within the U.S...

  • Animal Diversity Web: Bufo americanus
  • Photograph and audio recording of male American Toad