Green toads are desert-dwelling toads whose habitats include the northern Chihuahuan desert. This desert includes shrubs, semi-desert, and shrub steppe habitats. Many of these areas are unvegetated. Green toads burrow in mesquite (Prosopis) shrubs, which provide shelter and a means to regulate the toads body temperature.
During the dry season, green toads can be found under rocks. After rainfall, green toads will breed in temporary water sources such as roadside ditches and vernal pools. Seymour (1972) found that juvenile toads will bask on mud banks in an attempt to increase their internal body temperature to as high as 30 °C. Toadlets will also seek refuge in fissures in the mud.
Elevational limits or ranges have not been reported. However, those populations at higher, cooler elevations use burrows for a longer amount of time than those at lower elevations. (Boeing, et al., 2014; Goldberg, 2019; Lanoo, 2005; Seymour, 1972; Taggart and Rieldle, 2017)
Adult green toads, like their name suggests, are green with a mix of yellow. Both male and females have black spots. Often, these black spots fuse together to form black striations on their bodies. The ventral side of both sexes is white and lacks spots. Male green toads have black throats, while females’ throats are white or yellow. Both sexes have flat, wedge shaped heads.
Male green toads are smaller than females. Torres-Cervantes et al. (2019) reported lengths and weights for green toads in the Chihuahuan Desert. Males’ average size was 36.6 mm snout-vent length (SVL) (range 31.5 - 45.3 mm) and females average 43.2 mm SVL (range 41.8–44.0 mm). Female green toads' body mass averaged 10.0 g (range 9.2 - 10.7 g). Male mass averaged 6.0 (range 3.0 – 9.5 g). In other studies, adult females reached 54 mm SVL, while adult males were as small as 26 mm post-metamorphosis.
Green toads can release toxins through their parotoid glands in their skin. The toxin is cardiotoxic steroids, which is undesirable to predators.
Green toad tadpoles have rounded bodies. Their anal tube opening is located on the right side of their tail fins. Their eyes are located dorsally and the tail fins are not fully developed. Their abdomens are black with gold flecks. Tadpoles are otherwise transparent. They hatch at lengths between 3.1 to 3.4 mm. (Goldberg, 2019; Lanoo, 2005; Taggart and Rieldle, 2017; Torres-Cervantes, et al., 2019)
Green toads exhibit indeterminate growth. Like all toads, they go through metamorphosis from tadpole to adult. Green toads lay their eggs in small strings. The eggs attach to herbaceous stems, including grass. The ova size from two samples was 0.98 mm and 1.15 mm. Embryos found in southwest Arizona hatched within 24 hours with water temperatures at 33.2 °C. When water temperature was at 18.2 °C, the time required for hatching was 140 hours. Green toads’ average length at hatching is 3.1 to 3.4 mm.
There is a wide range of developmental dates. Metamorphosis typically takes less than 3 weeks. However, in Kansas, the tadpole stage exceeded 25 days. Taggart (1997) found development from zygote to juvenile lasted only 8 days.
Green toad larval development is dependent on environmental factors, like the amount of rainfall and temperature. Metamorphosis ends around froglet lengths of 19-20 SVL. Males are sexually mature at lengths of 26-41 mm SVL, while females are mature at 31-46 mm SVL. Males in southwest Mexico have been reported to begin calling at 37 mm SVL. In the same study, female green toads in amplexus ranged between 44-54 mm SVL. (Boeing, et al., 2014; Goldberg, 2019; Lanoo, 2005)
Green toads mate seasonally from late March to July, immediately after heavy rainfall. They mate in vernal pools. During this time, males attract females through their calls in chorus. Mating occurs via amplexus and reproduction occurs externally when eggs are released in tandem. Reproductively-active males are 26 to 41 mm SVL. Male green toads join choruses around 37 mm SVL. In southwest New Mexico, females in amplexus were 44 to 54 mm SVL. Green toads have many mating partners during mating season and are polygynandrous. (Boeing, et al., 2014; Goldberg, 2019; Lanoo, 2005)
Green toads are iteroparous, leaving their burrows after heavy rainfall to mate. Some green toads will travel several kilometers to different breeding sites with water. Green toads will migrate to multiple bodies of water during one season. Male green toads join in chorus to attract females. Female green toads will locate males to mate. These anurans exhibit rapid short-term breeding events just after heavy rainfall. Their breeding often lasts one night. Reproductively-active males are 26 to 41 mm SVL. In southwest New Mexico, females in amplexus were 44 to 54 mm SVL. During amplexus, female green toads lay, on average, 1,287 eggs. Green toad eggs are laid in small strings. The eggs attach to herbaceous stems, including grass. Egg size ranges from 0.98 mm to 1.15 mm.
Embryos found in southwest Arizona hatched within 24 hours with water temperatures at 33.2 °C. When water temperature was at 18.2 °C, the time required for hatching was 140 hours. Tadpoles are immediately independent at hatching.
Parental investment for green toads is limited to the act of mating. They leave egg masses attached to herbaceous stems in water, and then provide no further care. At hatching, the tadpoles are independent. (Lanoo, 2005)
The longevity of green toads is unknown. Most green toads will not survive to adult size in the wild. In captivity, the longest life span reported was 12.4 years. American toads (Anaxyrus americanus) have a maximum lifespan of 10 years in the wild. Green toads likely have similar life spans in the wild. (Lanoo, 2005; Slavens and Slavens, 2018; Smirina, 1994)
Male green toads join in chorus to attract female green toads. There is no correlation between toad size, temperature, and variation in calls. Male green toads do not use active search methods to locate females. They mate from late March until July during nocturnal hours. Breeding occurs in aquatic locations. They only come out of burrows for mating and mate via amplexus (external fertilization).
Green toads are inactive unless it is humid or after heavy rainfalls. From September to May, green toads typically remain inactive (hibernating) and below ground. Green toads do not swim great distances, only using temporary pools to breed. They do hop on terrestrial ground. They do not migrate seasonally, but they sometimes travel several kilometers to reach breeding pools. Here they join large choruses of frogs.
During the dry season, they are solitary, finding shelter under rocks. They use sunlight to thermoregulate and absorb water while basking. To absorb water, they place their anterior side into the soil. (Boeing, et al., 2014; Lanoo, 2005; Seymour, 1972; Sullivan, 1984)
Home range size for green toads is unknown. During breeding, calling males can be found 0.5 to 0.3 m apart from each other. Occasionally, and they can be as close as 0.1 m from each other. They are not known to actively defend an area. (Lanoo, 2005)
Green toads communicate through calls in chorus. Males’ advertisement calls are described to be similar to crickets, as long high-pitched trills. They typically last less than 7 seconds. The breeding choruses begin after rainfall and last 1 to 3 days. The female locates the male via choruses (acoustics) to mate. Male toads do not search for females.
Vision is utilized in mate recognition, as males and females can be differentiated by throat color. Males have black colored throats and females have white or yellow. When mating, they use tactile efforts, as males grasp females in amplexus.
When threatened, green toads release indolealkylamines from their skin, including paratoid glands. The chemicals are distasteful to predators. (Lanoo, 2005; Luria-Manzano and Ramirez-Bautista, 2019; Sullivan, 1984; Taggart and Rieldle, 2017)
Green toad tadpoles feed on algae found in the substrate of ephemeral pools. They also feed on detritus and periphyton. Luria-Manzano and Ramirez-Bautista (2019) reported diets of 10 green frogs in the Chihuahuan Desert. Their diets included beetles (Order Coleoptera, 12% of volume), ants (Order Hymenoptera, 31%), termites (Isoptera, 56%), caterpillars (Order Lepidoptera, 0.5%), and earwigs (Dermaptera, 0.02%). Plant matter was also found in stomach contents. They may also eat a variety of insects, like grasshoppers and crickets (Order Orthoptera). (Lanoo, 2005; Luria-Manzano and Ramirez-Bautista, 2019)
Green toad tadpoles are more likely to be preyed upon than adults. Known predators of tadpoles and adults are black-necked garter snakes (Thamnophis cyrtopsis). Eggs and tadpoles are known to be attacked by dragonfly larvae (Order Odonata). Because adult green toads are fossorial and terrestrial, many of the predators include snakes. Some of the snakes include gopher snakes (Pituophis catenifer), checkered garter snakes (Thamnophis marcianus), plains garter snakes (Thamnophis radix), and western hog-nosed snakes (Heterodon nasicus). Green toads are also attacked by invertebrates including giant water bugs (family Belostomatidae) and water scavenger beetles (family Hydrophilidae). American bullfrogs (Lithobates catesbeianus) also prey on these toads.
Green toad adults avoid predation by remaining underground for much of the year. If they become threatened during choruses, green toads will retreat underwater or hide in vegetation. Green toads can release toxins (cardiotoxic steroids) through their parotoid glands. (Lanoo, 2005)
Known predators of green toads are snakes, and predaceous aquatic insects. Green toads likely feed opportunistically on a variety of invertebrates.
Parasites of green toads in New Mexico include tapeworms (Distoichometra bufonis) and roundworms or nematodes (Rhabdias americanus, Aplecctana incerta, Alpecctana itzocanenis, and Physaloptera pirurida). In central Texas, these toads were affected by endoparasites including ciliates (Nyctotherus cordiformis), and cnidarian myxizoans (Myxidium serotinum). Green toads’ blood samples were negative for endoparasites like apicomplexans and trypanosomes. Unidentified protozoans in the SAR clade, family Opalinidae, also were found in Texas. (Lanoo, 2005)
Green toads have occurred in amphibian trade in Texas. Many of them were exported to other countries by online sources. Anurans export and import is on the rise in Texas. (Prestridge, 2009)
There are no known adverse economic effects of green toads on humans.
Green toads do not have special status on the US federal list, CITES, and the State of Michigan List. They are listed as a species of "Least Concern" on the IUCN Red List. Green toads are protected by Kansas. They are also protected by Mexican law.
The historical abundance of green toads is not known, but they are often found in locations with suitable habitat. Their localized populations have likely declined, due to habitat loss, including temporary wetlands. Changes in land-use have led to many green toad habitats becoming unsuitable.
There have been attempts in Kansas to reintroduce green toads into historical areas. However, no attempts have been successful. There is not a recovery plan for green toads. (Hammerson and Santos-Barrera, 2004; Lanoo, 2005; Taggart, 2021)
Sydni Smith (author), Radford University, Karen Powers (editor), Radford University, Victoria Raulerson (editor), Radford University, Christopher Wozniak (editor), Radford University, Genevieve Barnett (editor), Colorado State University.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
uses sound to communicate
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
uses smells or other chemicals to communicate
to jointly display, usually with sounds, at the same time as two or more other individuals of the same or different species
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
fertilization takes place outside the female's body
union of egg and spermatozoan
Referring to a burrowing life-style or behavior, specialized for digging or burrowing.
An animal that eats mainly plants or parts of plants.
the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.
Animals with indeterminate growth continue to grow throughout their lives.
An animal that eats mainly insects or spiders.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
the business of buying and selling animals for people to keep in their homes as pets.
an animal which has a substance capable of killing, injuring, or impairing other animals through its chemical action (for example, the skin of poison dart frogs).
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
specialized for leaping or bounding locomotion; jumps or hops.
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
associates with others of its species; forms social groups.
uses touch to communicate
Living on the ground.
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
uses sight to communicate
Altig, R., R. McDiarmid. 2015. Handbook of Larval Amphibians of the United States and Canada. Ithaca, New York: Cornell University Press.
Boeing, W., K. Griffis-kyle, J. Jungels. 2014. Anuran habitat associations in the northern Chihuahuan Desert, USA. Journal of Herpetology, 48/1: 103-110.
Ceballos, R., P. Ehrlich, G. Dirzo. 2017. Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines. Proceedings of the National Academy of Sciences of the United States of America, 114/30: 89-96.
Goldberg, S. 2019. Notes on reproduction of green toads Anaxyrus debilis (Anura: Bufonidae) from New Mexico. Sonoran Herpetologist, 32/1: 3-4.
Griffis-Kyle, K., S. Kyle, J. Jungels. 2011. Use of breeding sites by arid-land toads in: Landscape-level factors. The Southwestern Naturalist, 56/2: 251-255.
Hammerson, G., G. Santos-Barrera. 2004. "Anaxyrus debilis" (On-line). The IUCN Red List of Threatened Species 2004: e.T54626A11177308. Accessed September 06, 2021 at https://dx.doi.org/10.2305/IUCN.UK.2004.RLTS.T54626A11177308.en.
Harrings, N., W. Boeing. 2014. Desert anuran occurrence and detection in artificial breeding habitats. Herpetologica, 70/2: 123-134.
Jimenez-Arcos, V., E. Centenero-Alcala, L. Vazquez Reyes, C. Blair, S. Santa Cruz-Padilla. 2014. Agalychnis dacnicolor—predation. Herpetological Review, 45/4: 677.
Lanoo, M. 2005. Amphibian Declines: The Conservation Status of United States Species. Los Angeles, California: University of California Press.
Luria-Manzano, R., A. Ramirez-Bautista. 2019. Ontogenetic variation in the diet of the anuran community from a semi-arid environment in the southeastern Chihuahuan Desert. PeerJ, 7: e7908. Accessed September 07, 2021 at doi: 10.7717/peerj.7908.
Maciel, N., C. Schwartz, A. Sebben, M. Castro, M. de Sousa, W. Fontes, E. Schwartz, O. Pires Júnior. 2003. Composition of indolealkylamines of Bufo rubescens cutaneous secretions compared to six other Brazilian bufonids with phylogenetic implications. Comparative Biochemistry and Physiology Part B Biochemistry and Molecular Biology, 134/4: 641. Accessed September 18, 2021 at DOI:10.1016/S1096-4959(03)00022-8.
McAllister, C., C. Bursey, S. Trauth. 2008. New host and geographic distribution records for some endoparasites (Myxosporea, Trematoda, Cestoidea, Nematoda) of amphibians and reptiles from Arkansas and Texas, U.S.A. Comparative Parasitology, 75/2: 241-254.
Powell, R., R. Conant, J. Collins. 2016. Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America, Fourth Edition. Boston, Massachusetts and New York, New York: Houghton Mifflin Harcourt.
Prestridge, H. 2009. Amphibian and Reptile Trade in Texas: Current Status and Trends (Master's Thesis). College Station, Texas: Texas A&M University.
Seymour, R. 1972. Behavioral thermoregulation by juvenile green toads, Bufo debilis. Copeia, 1972/3: 572-575.
Slavens, F., K. Slavens. 2018. "Frank and Kate's Webpage" (On-line). Accessed September 07, 2021 at http://www.pondturtle.com.
Smirina, E. 1994. Age determination and longevity in amphibians. Gerontology, 40(2-4): 133-146. Accessed November 18, 2021 at doi: 10.1159/000213583 PMID: 7926852.
Smith, G., J. Lemos-Espinal, A. Burner, K. Winter, C. Dayer. 2011. Diets of three species of bufonids (Amphibia, Anura) from northern Mexico. Western North American Naturalist, 71/4: 563-569.
Sullivan, B. 1984. Advertisement call variation and observations on breeding behavior of Bufo debilis and B. punctatus. Journal of Herpetology, 18/4: 406-411.
Taggart, T., J. Rieldle. 2017. A Pocket Guide to Kansas Amphibians, Turtles and Lizards. Wichita, Kansas: Great Plains Nature Center. Accessed September 14, 2021 at https://gpnc.org/wp-content/uploads/sites/32/2018/02/KS-Amphibians-Lizards-Turtles.pdf.
Taggart, T. 2021. "Chihuahuan Green Toad" (On-line). Kansas Herpetofaunal Atlas. Accessed November 17, 2021 at https://webapps.fhsu.edu/ksherp/account.aspx?o=30&t=3.
Torres-Cervantes, R., A. Ramirez-Bautista, C. Islas, R. Cruz-Elizalde, U. Hernandez-Salinas. 2019. Morphology and reproductive patterns of an assemblage of anurans from the Chihuahuan Desert Region, Mexico. Journal of Arid Environments, 165: 28-33. Accessed November 17, 2021 at doi: 10.1016/j.jaridenv.2019.03.004.
Wright, A., A. Wright. 1949. Handbook of Frogs and Toads of the United States and Canada, Third Edition. Ithaca, New York: Comstock Publishing Associates.