The oak toad (''Anaxyrus quercicus'') is a species of
toad
Toad is a common name for certain frogs, especially of the family Bufonidae, that are characterized by dry, leathery skin, short legs, and large bumps covering the parotoid glands.
A distinction between frogs and toads is not made in scientif ...
in the family
Bufonidae. It is
endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
to the coastal regions of southeastern
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
.
[University of Michigan Museum of Zoology.](_blank)
Retrieved on 21 October 2008. It is regarded as the smallest species of toad in North America, with a length of .
Description
The oak toad can be identified by its light mid-dorsal stripe, variable brown and black spots, and proportionally large
parotoid gland
The parotoid gland (alternatively, paratoid gland) is an external skin gland on the back, neck, and shoulder of toads and some frogs and salamanders. It can secrete a number of milky alkaloid substances (depending on the species) known collective ...
s. One of the most remarkable features of this species is its small adult size relative to other toads.

The male can be distinguished from the female by his clear white belly and a slightly distended, loose flap of skin beneath the mouth, which expands into the
vocal sac
The vocal sac is the flexible membrane of skin possessed by most male frogs and toads. The purpose of the vocal sac is usually as an amplification of their mating or advertisement call. The presence or development of the vocal sac is one way o ...
. The female has a dark-spotted belly and lacks a vocal sac.
Habitat and distribution
The oak toad is native to the coastal regions of the southeastern United States, ranging from eastern Louisiana to southeast Virginia and south throughout Florida. It is found in a variety of habitats, including sandy pine flatwoods and oak scrub, open pine and pine-oak woods, pine or oak savanna with sandy soils, and maritime forests. Oak toads prefer open-canopied pine flatwoods with grassy ground cover, and they are generally found in moist, grassy areas near pine or oak savannahs with sandy soil. They are also found in vernal pools and freshwater wetlands.
[Oak Toad, ''Bufo quercicus''.](_blank)
USGS, Northern Prairie Wildlife Research Center, Checklist of Amphibian Species and Identification Guide. Retrieved 30 March 2013. [https://animaldiversity.org/accounts/Anaxyrus_quercicus/]
Behavior
It is mostly diurnal and spends much of its time burrowed into the loose soil of its habitat. It may remain in its burrow during the winter, often in hibernation.
Breeding takes place in shallow pools that accumulate during heavy rains. The male expands his distinctive elongated vocal sac to produce a chirping call. The breeding season extends from April to October, peaking early on.
[Harper, F. 1931. A dweller in the piney woods. ''Science Monthly'' 32 176–81.] Heavy, warm spring rains stimulate mating behavior.
[Wright, A. H. and A. A. Wright. 1949. ''Handbook of Frogs and Toads of the United States and Canada''. Third edition. Comstock Publishing Associates, Ithaca, New York.] 
An average of 300–500 eggs are laid in short strands of 3 to 8 eggs each, with each egg about a millimeter wide.
The strands are attached to vegetation, usually submerged blades of grass beneath the surface.
Energy investment in producing this quantity of eggs is significant, and many females are found dead during the mating season due to the rigors of the process. Fertilization takes place externally, with sperm being released in the vicinity of the eggs. As with other species of toad, the male oak toad has a
Bidder's organ
Bidder's organ is a spherical, brownish organ in most members of the family Bufonidae (true toads). The organ is located just in front of the kidney, or mesonephros. It is formed at the cranial tip of the male and female gonad during the larval sta ...
, which can become a functional ovary in the event of
testicular malfunction.
[''Bufo quercicus''.](_blank)
Virginia Department of Game & Inland Fisheries. 2004. Retrieved on 20 October 2005.
Diet
The oak toad is a small, terrestrial frog that feeds on a variety of insects and other small invertebrates. Its diet consists primarily of ants, beetles, and spiders, as well as other insects and arthropods. The oak toad spends much of its time foraging for food, using its long, sticky tongue to capture prey. The oak toad eats mainly small insects and other arthropods. The adult has a strong preference for
ants.
[Lannoo, M. ''Amphibian Declines: The Conservation Status of United States Species.'' University of California Press. 2000. 432-33.]
Life cycle
Eggs develop quickly, hatching in a mere 24 to 36 hours.
The
tadpole
A tadpole is the larval stage in the biological life cycle of an amphibian. Most tadpoles are fully aquatic, though some species of amphibians have tadpoles that are terrestrial. Tadpoles have some fish-like features that may not be found i ...
reaches a maximum length of . It is grayish olive or grape-green dorsally and purplish ventrally. The tail has 6 or 7 black saddle marks.
The tadpole completes metamorphosis into a juvenile toadlet in 4 to 6 weeks, and it reaches adulthood and sexual maturity at 1.5 to 2.3 years of age.
The length of the lifespan is unclear.
There are records of specimens living for four years in captivity,
[Ashton, R. E., Jr. and P. S. Ashton. 1988. ''Handbook of Reptiles and Amphibians of Florida: Part Three: The Amphibians.'' Windward Publishing, Miami, Florida.][Wright, A. 1932. ''Life Histories of the Frogs of Okefinokee Swamp, Georgia: North American Salientia (Anura) No. 2.'' United States: Cornell University Press.] and the reported average lifespan in captivity is 1.9 years.
[Bowler, J. K., 1975. Longevity of reptiles and amphibians in N. American collections as of 1 November 1975. Society for the Study of Amphibians and Reptiles, Miscellaneous Publications, Herpetological Circular 6 1-32.]
Predation
The primary predators of the oak toad are snakes, particularly
hognosed snakes, which are specialized for eating toads. Other predators include
garter snakes and
gopher frogs.
[Behler, J. 1979. ''The Audubon Society Field Guide to North American Reptiles & Amphibians.'' New York: Chanticleer Press, Inc.]
As with many bufonids, the oak toad inflates its body in
unkenreflex
Unkenreflex – interchangeably referred to as unken reflex (''Unke'' is the German word for the genus of fire-bellied toads) – is a defensive posture adopted by several branches of the amphibian class – including salamanders, toads, and cert ...
when confronted by a potential predator. It secretes toxins from its
parotoid gland
The parotoid gland (alternatively, paratoid gland) is an external skin gland on the back, neck, and shoulder of toads and some frogs and salamanders. It can secrete a number of milky alkaloid substances (depending on the species) known collective ...
s and urinates when threatened. The male may chirp as a response to predators. Eggs also appear to have some toxic properties.
References
Further reading
''Anaxyrus quercicus''.AmphibiaWeb.
{{Taxonbar, from=Q2298771
Anaxyrus
Fauna of the Southeastern United States
Amphibians of the United States
Endemic fauna of the United States
Amphibians described in 1840
Taxa named by John Edwards Holbrook
Taxonomy articles created by Polbot