American toad
American toad (Anaxyrus americanus)
Taxonomy
| Kingdom | Phylum | Class | Order | Family | Genus | |
|---|---|---|---|---|---|---|
| Classification | Animalia | Chordata | Amphibia | Anura | Bufonidae | Anaxyrus |
Their name has recently changed from (Bufo americanus) to (Anaxyrus americanus).
Description
The American toad is a common toad species that can be found throughout the Eastern and Central parts of the United States and Canada. This species is a medium size toad that grows up to 5-9 cm or 2-4 inches in length with females generally being slightly larger than males. Its coloration can change depending on the temperature, humidity, and stress levels of the environment. American toads are predominantly brown and can display hues of red or olive green. Their bellies are whitish or yellow, usually with dark spots. They have noticeable warts on their skin, including two large ones behind their eyes. The warts behind their eyes are their parotoid glands which are major salivary glands found in animals. These parotoid glands secrete a bufotoxin that is used to deter predators. Bufotoxin is a milky toxin made up of steroid lactones and can cause illness and death in small animals. The bufotoxin in American toads is not fatal to humans but can cause allergic reactions. American toads typically only live to be a few years old in the wild, however, they can live up to around 10 years old in capacity. There is even a case of an American toad living 36 years in capacity until it died due to an accident.
Range and Subspecies
American toads can be found throughout most of the Eastern and Central parts of the United States and Canada. They prefer cool woodlands with lots of moisture but can live in meadows, fields, and gardens. American toads require small freshwater ponds for their early days when they start as tadpoles. As they develop, they hydrate their bodies by absorbing moisture through their thin skin, so they require a moist environment to survive. There are currently two recognized subspecies of the American toad - the Eastern American toad (Anaxyrus americanus) and the Dwarf American toad (Anaxyrus charlesmithi). The range of the Dwarf American toad is more concentrated and they are found in more southern states while the Eastern American toad occupies a range spanning the East coast of the United States and Canada, excluding the southernmost states.
Life Cycle and Behavior
Depending on temperature and location, mating can being as early as March and ends in July. The males will find a shallow spot in wetlands or ponds and call to attract females. Males generally only call at night but will call during wet days during the peak of mating season. [1] Once the mating takes place the female will lay from 2,000-20,000 eggs in a long strand. The eggs will hatch after 3-12 days, typically from around June to August. Once the eggs hatch, they develop into tadpoles and become fully grown in 60 days. An American Toad will reach sexual maturity after 2-4 years. Once the toads reach adulthood they feed during the early morning into the night, as they are mainly nocturnal. American toads often hide in leaf litter to avoid predators. The toads will burrow in moist soils and hibernate in these burrows during the winter.
Diet and Predators
When American toads start off as tadpoles, they are herbivorous and primarily feed on decaying plants. When they become adults, they become carnivorous and eat small creatures such as insects, spiders, worms, and snails. The predators of the American toad include birds, snakes, and small mammals such as raccoons and skunks. There are certain snakes, such as the eastern hognose snake, which is specialized in eating toads due to its immunity to the American toad's bufotoxin. Toads often pee on themselves to make themselves a less appealing meal when they are facing a predator that is unaffected by their toxins. Another defensive behavior is that toads will enlarge their bodies by puffing up to seem too large for a snake to consume.
References
1. Altig, Ronald, et al. Handbook of Larval Amphibians of the United States and Canada. 1st ed., Cornell University Press, 2015. JSTOR, www.jstor.org/stable/10.7591/j.ctt1tm7g59. Accessed 12 Apr. 2021.
2. “American Toad.” Illinois Department of Natural Resources, dnr.illinois.gov/education/wildaboutpages/wildaboutfrogs/waftamericantoad.html. Accessed 12 May 2023.
3. (“Eastern American Toad Fact Sheet - Signs of the Seasons: A New England Phenology Program - University of Maine Cooperative Extension”) “IUCN Red List of Threatened Species.” IUCN Red List of Threatened Species, https://www.iucnredlist.org/species/54570/56843565. Accessed 12 Apr. 2021.
4. Grossman, Stacey. “Anaxyrus Americanus (American Toad).” Animal Diversity Web, animaldiversity.org/accounts/Anaxyrus_americanus/.
5. “IUCN Red List of Threatened Species.” IUCN Red List of Threatened Species, https://www.iucnredlist.org/species/54570/56843565. Accessed 12 Apr. 2021.
6. Pauly, Gregory B., et al. “THE HISTORY OF A NEARCTIC COLONIZATION: MOLECULAR PHYLOGENETICS AND BIOGEOGRAPHY OF THE NEARCTIC TOADS (BUFO).” Evolution, no. 11, The Society for the Study of Evolution, 2004, p. 2517. Crossref, doi:10.1554/04-208.
7. “Toads.” National Wildlife Federation, www.nwf.org/Educational-Resources/Wildlife-Guide/Amphibians/Toads. Accessed 12 May 2023.
8. Vaughan, Andres, and Joseph R. Mendelson. “Taxonomy and Ecology of the Central American Toads of the Genus Crepidophryne (Anura: Bufonidae).” Copeia, no. 2, American Society of Ichthyologists and Herpetologists (ASIH), May 2007, pp. 304–14. Crossref, doi:10.1643/0045-8511(2007)7[304:taeotc]2.0.co;2.