Animal Diversity Web

Ge­o­graphic Range

Oak toads are found in the coastal plains of the south­east­ern United States. They are found from the south­ern tip of Florida to the south­ern por­tion of Vir­ginia and to parts of east­ern Louisiana. ("The Pel­i­can Post", 2004; Anony­mous, 2000; Behler, 1979)

• Biogeographic Regions
• nearctic
  • native

Habi­tat

Oak toads 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. They breed in shal­low pools, ditches, and ponds. (Behler, 1979; Knapp, 06/28/03; Wright, 1932)

• Habitat Regions
• temperate
• terrestrial
• freshwater

• Terrestrial Biomes
• savanna or grassland
• forest

• Aquatic Biomes
• lakes and ponds
• rivers and streams
• temporary pools

• Wetlands
• marsh

Phys­i­cal De­scrip­tion

Anaxyrus quer­ci­cus is the small­est toad species in North Amer­ica, rang­ing from 1.9 to 3.3 cm. It is so small that adults found in the wild were com­monly clas­si­fied as “half-grown” or “ju­ve­nile” south­ern toads (Bufo lentig­i­nosus). They have a short head with a pointed nose and the short, flat body is black or brown in color (color can change with tem­per­a­ture) with a long dor­sal stripe that may be white, cream, yel­low, or or­ange. There are 4 to 5 pairs of dark blotches found on the back. The back is finely tu­ber­cu­late, with the fine bumps (red, or­ange or red­dish-brown in color) giv­ing it a rough tex­ture. The un­der­side is gray­ish white and has no blotches, but is cov­ered in tu­ber­cles. Oak toads have elon­gated, teardrop-shaped para­toid glands that ex­tend down ei­ther side. These glands house a poi­so­nous fluid used deter preda­tors. Males can be dis­tin­guished by their dark, dusky col­ored throats. (Anony­mous, 2004; Dick­er­son, 1969; Knapp, 06/28/03; Wright, 1932)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry
• poisonous

• Sexual Dimorphism
• female larger
• sexes shaped differently

• Range length

  19 to 33 mm

  0.75 to 1.30 in

De­vel­op­ment

In the span of two months, tad­poles hatch from their eggs and go through meta­mor­pho­sis, be­com­ing adult toads. Tad­poles have a gray­ish olive or grape green color to the body due to close set dots against a black back­ground. The un­der­side has a pale pur­plish color. the tail has 6-7 black sad­dles (col­oration that wraps around the tail to a de­gree). Ju­ve­nile toads re­main near the natal pond for a few days be­fore mov­ing to land, where they will spend the ma­jor­ity of their time. (Anony­mous, 2004; Wright, 1932)

• Development - Life Cycle
• metamorphosis

Re­pro­duc­tion

Males ar­rive be­fore fe­males at shal­low, semi-per­ma­nent or tem­po­rary ponds, and road­side drainage ditches. At breed­ing ponds males es­tab­lish ter­ri­to­ries and begin call­ing fe­males with a high-pitched chirp. Ap­prox­i­mately 100-250 eggs are laid at a time in long strings, held to­gether by a gelati­nous ma­te­r­ial, and ei­ther float or stick to sur­faces. Fer­til­iza­tion takes place ex­ter­nally when the male frog re­leases his sperm in the vicin­ity of the eggs. In the case of a tes­tic­u­lar mal­func­tion, male oak toads have an ovary that will be­come func­tional, al­low­ing them to breed as fe­males. (Anony­mous, 2000; Wright, 1932)

• Mating System
• polygynandrous (promiscuous)

Male and fe­male oak toads form a pair when the male grabs onto the fe­male from be­hind in a po­si­tion re­ferred to as am­plexus. The male stays at­tached to the fe­male until she re­leases her eggs into the water. The fe­male emits sev­eral eggs and then the male re­leases sperm into the water. The fe­male will con­tinue to re­lease eggs. The eggs are re­leased in bars con­tain­ing 4-6 eggs apiece. Each fe­male will lay about 700 eggs in total in a sin­gle sea­son. These eggs will hatch within 3 to 3.5 days and de­velop into adult oak toads within 2 months. (Anony­mous, 2000; Wright, 1932)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
  • external
• oviparous

• Breeding interval

  Oak toads are seasonal breeders and breeds once per year.

• Breeding season

  Oak toads breed from April to September or October. The mating season often begins with the arrival of warmer temperatures and thunderstorms. The interval of ovulation is approximately late May-mid August.

• Average number of offspring

  700

• Range time to hatching

  72 to 80 hours

• Average age at sexual or reproductive maturity (female)

  2 months

• Average age at sexual or reproductive maturity (male)

  2 months

The ex­tent of fe­male en­ergy in­vest­ment is great dur­ing the ovu­la­tion and mat­ing pe­ri­ods, as many fe­males are found dead dur­ing these pe­ri­ods due to ei­ther the rig­ors of pair for­ma­tion or en­ergy in­vest­ment in the lay­ing of eggs. Once the eggs are fer­til­ized and at­tached to a sur­face, there is no fur­ther parental care. (Wright, 1932)

• Parental Investment
• no parental involvement
• pre-fertilization
  • provisioning

Lifes­pan/Longevity

Oak toad lifes­pans are not well known.

• Average lifespan
  Status: captivity

  1.9 years

  Max Planck Institute for Demographic Research

Be­hav­ior

Oak toads are ac­tive dur­ing the day, but oc­ca­sion­ally they are found at night tak­ing part in breed­ing cho­ruses. Out­side of the breed­ing sea­son, oak toads are soli­tary. They spend most of the day buried in the sand or hid­ing under leaves or rocks. (Behler, 1979; Dick­er­son, 1969)

• Key Behaviors
• terricolous
• saltatorial
• diurnal
• crepuscular
• motile
• hibernation
• solitary
• territorial

Com­mu­ni­ca­tion and Per­cep­tion

Male oak toads make a high-pitched, bird-like chirp­ing calls to at­tract fe­males. Oak toads per­ceive their en­vi­ron­ment through vi­sual, au­di­tory, tac­tile, and chem­i­cal senses. ("The Pel­i­can Post", 2004; Behler, 1979; Dick­er­son, 1969; Wright, 1932)

• Communication Channels
• acoustic

• Other Communication Modes
• choruses

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

Oak toads are preda­ceous and feed pri­mar­ily on ter­res­trial in­sects and other small arthro­pods. (Knapp, 06/28/03; Wright, 1932)

• Primary Diet
• carnivore
  • insectivore
  • eats non-insect arthropods

• Animal Foods
• insects
• terrestrial non-insect arthropods

Pre­da­tion

The pri­mary preda­tors of oak toads are snakes, par­tic­u­larly hog­nosed snakes (Het­erodon platirhi­nos), spe­cial­ized for eat­ing toads. Other preda­tors of oak toads are garter snakes (Thamnophis sir­talis) and go­pher frogs (Litho­bates capito). (Behler, 1979; Wright, 1932)

• Anti-predator Adaptations
• cryptic

• Known Predators

  • hognosed snakes (Heterodon platirhinos)
  • garter snakes (Thamnophis sirtalis)
  • gopher frogs (Lithobates capito)

Ecosys­tem Roles

Al­though smaller than other toads, the Oak Toad still plays a cru­cial role in in­sect pop­u­la­tion con­trol. (Behler, 1979)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Oak toads help con­trol pop­u­la­tion lev­els of in­sects and other small arthro­pods.

• Positive Impacts
• controls pest population

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

There are no known neg­a­tive im­pacts of oak toads on hu­mans.

Con­ser­va­tion Sta­tus

Oak toad pop­u­la­tions are de­clin­ing through­out many states. In Vir­ginia it is listed as a species of spe­cial con­cern (one that is not yet threat­ened but is ex­pected to be in the near fu­ture). Also, in North Car­olina, it is on the watch list for species that may be fac­ing prob­lems in the near fu­ture. A pos­si­ble cause for de­creases in oak toad pop­u­la­tions is the clear­ing of the sa­van­nah for­est habi­tats they pre­fer. (Anony­mous, 2000)

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  No special status

• CITES

  No special status

Con­trib­u­tors

Tanya Dewey (ed­i­tor), An­i­mal Di­ver­sity Web.

Ryan Buck­ley (au­thor), Kala­ma­zoo Col­lege, Ann Fraser (ed­i­tor, in­struc­tor), Kala­ma­zoo Col­lege.

Ref­er­ences

2004. "The Pel­i­can Post" (On-line). Na­ture's Cal­en­der. Ac­cessed Oc­to­ber 28, 2005 at http://​www.​weeksbay.​org/​newsletter/​Win_​2003/​Pg6_​2.​htm.

Anony­mous, 2000. "Geor­gia Wildlife Web" (On-line). Toads. Ac­cessed Oc­to­ber 20, 2005 at http://​museum.​nhm.​uga.​edu/​gawildlife/​amphibians/​anura/​bufonidae/​bquercicus.​html.

Anony­mous, 2004. "Vir­ginia De­part­ment of Game & In­land Fish­eries" (On-line). Vir­ginia Wildlife In­for­ma­tion: Bufo Quer­ci­cus. Ac­cessed Oc­to­ber 20, 2005 at http://​www.​dgif.​state.​va.​us/​wildlife/​species/​display.​asp?​id=020063.

Behler, J. 1979. The Audubon So­ci­ety Field Guide to North Amer­i­can Rep­tiles & Am­phib­ians. New York: Chan­ti­cleer Press Inc..

Dick­er­son, M. 1969. The Frog Book: north amer­i­can toads and frogs, with a study of the habits and life his­to­ries of those of the north­ern states. Canada: Gen­eral Pub­lish­ing Com­pany.

Knapp, W. 06/28/03. "The Frogs & Toads of Geor­gia" (On-line). Oak Toad- Bufo Quer­ci­cus. Ac­cessed Oc­to­ber 20, 2005 at http://​wwknapp.​home.​mindspring.​com/​docs/​oak.​toad.​html.

Wright, A. 1932. Life His­to­ries of the Frogs of Okefi­no­kee Swamp, Gee­or­gia: North Amer­i­can Salien­tia (Anura) No. 2. United States: Cor­nell Uni­ver­sity Press.