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Anaxyrus speciosusTexas Toad

By Janita Lyde

Geographic Range

Texas toads (Anaxyrus speciosus), are native to the western two-thirds of Texas, southeastern New Mexico, western Oklahoma. Their range continues southward into northeastern and north-central Mexico. This includes the Mexican states of Chihuahua, Coahuila, Nuevo Leon, and Tamaulipas. Texas toads are abundant in south Texas in Big Bend National Park, and Little Sahara State Park in Oklahoma. In Mexico, these toads are abundant in the Tamaulipas Desert. (Dayton, et al., 2004; Farr, et al., 2013)

Habitat

Texas toads’ habitats change with their life stages. Tadpoles live in rivers, ponds, and streams, in sediment and within aquatic vegetation. As juveniles these toads become terrestrial, and dig into the cracks of mud, soil, and vegetation with high soil moisture. Adult toads live in desert areas close to an irrigation ditch or a water tank. They will also take refuge in grasslands, open woodlands, sandy soil, and in tunnel systems dug by Texas pocket gophers (Geomys personatus). Because they can feed under streetlights, they are thought to inhabit suburban locales, as well.

When Texas toads breed, they move temporarily to warm freshwater streams and small desert pools; they take residence in these areas during the months of April to September.

Texas toads are found at the average elevation of 149m. However, populations in New Mexico exist at elevational ranged from 900 to 1300 m. The IUCN SSC Amphibian Specialist Group (2021) lists their upper elevational limit at 1300 m. (Altig and McDiarmid, 2015; Dodd Jr, 2013; Hibbitts and Adams, 2015; IUCN SSC Amphibian Specialist Group, 2021; Lannoo, 2005)

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams
  • temporary pools
  • Range elevation
    1300 (high) m
    4265.09 (high) ft
  • Average elevation
    149 m
    488.85 ft

Physical Description

Texas toads have a round body, with gray and green skin. Like most toads, they possess bumpy skin with warts, and have brown and yellow speckles on their dorsal side. These toads have small paratoid glands (located posterior to the eyes) that secrete a toxin. As adults, males will weigh up to 645-680g, while the females are often larger, weighing 700-980g. Adult male Texas toads have an average snout-vent length (SVL) of 68 mm (range 52-78 mm), while adult females average 83mm (range 54-91mm) SVL.

Eggs are brown with speckles of yellow, possessing a jelly layer around them. Egg size ranges from 1.2-2.4mm and averages 1.8mm. The tadpoles have a pale white ventral area and have a pale green dorsal side. Tadpole SVL is 12-28mm and averages 19mm. The tails of the tadpoles are 60% of their total body length. (Altig and McDiarmid, 2015; Dayton, et al., 2004; Lannoo, 2005)

  • Sexual Dimorphism
  • female larger
  • Range mass
    645 to 980 g
    22.73 to 34.54 oz
  • Range length
    52 to 91 mm
    2.05 to 3.58 in

Development

Texas toads’ eggs are laid in a small pond, and they will begin to hatch within 2-3 days. Tadpole development will range from 18-60 days at a snout-vent length of 12.0 mm. The length of time depends on when ponds go dry. Once the toads metamorphose into the juvenile stage, they will grow for 7 months; during these months the juveniles’ tails will shrink, they will develop lungs and they will develop better use of their legs.

Lannoo reported on a study of young Texas toad growth rates, which were 10 mm per month. They reach maturity at lengths of 52–78 mm for males and 54–91 mm for females. Therefore, the growth rate study suggested that toads that hatched earlier in the breeding season could reach sexual maturity within a year. Those born later in the season might wait until their second year to breed. Texas toads will then slowly grow for the rest of their lives, up to 0.8 mm each year. (Altig and McDiarmid, 2015; Lannoo, 2005; Ramesh, et al., 2012)

Reproduction

Texas toads breed from April – September but only during or up to 4 days after heavy rainfall. Mating will take place in a temporary pool near permanent water such as streams, pools, and irrigation ditches. Male Texas toads will call to claim a territory at this temporary pool and will aggressively attack one another at this time. The males will use advertising calls to attract the females. The calls will occur all day and night lasting 1.5 seconds per trill, with 1 second of rest. But the chorus (all toads calling) can sound as if it is nonstop.

Female Texas toads will move towards the males, and they appear to choose louder-calling (larger) males over the small males. Once the females are close enough, males will grab the females in amplexus. If a female is grabbed a male that she deems unfit, she will attempt to swing him off. Successful mating efforts result in external fertilization of eggs with sperm. Multiple pairs may have egg masses in the same location, typically along the substrate at the base of underwater vegetation. (Dayton, et al., 2004; Goldberg, 2018; Lannoo, 2005)

Breeding occurs once a year from April until September, up to 4 days after a significant rainfall. The eggs are deposited in the breeding pool in clutches of 14-20 eggs, with a combined length of about 30mm long. Multiple pairs may lay leave clutches in the same location, in the substrate and at the base of underwater vegetation.

Each egg is about 1.4mm wide. The incubation period will take 3-4 days. After the eggs are laid, male Texas toads may stay by the breeding pool to ensure other males won’t harm the egg masses. Hatched tadpoles are about 10-12mm in length. At hatching, the tadpoles are on their own, as neither parent provides parental care.

Young toads reach maturity at lengths of 52–78 mm for males and 54–91 mm for females. Lannoo reported on a study of young Texas toad growth rates, which were 10 mm per month. This growth rate study suggested that toads that hatched earlier in the breeding season could reach sexual maturity within a year. Those born later in the season might wait until their second year to breed. (Farr, et al., 2013; Lannoo, 2005; Springer and Montaña, 2015)

  • Breeding interval
    Texas toads breed yearly
  • Breeding season
    April-September, within 4 d of heavy rainfall
  • Range number of offspring
    14 to 20
  • Range time to hatching
    3 to 4 days
  • Average time to independence
    0 minutes
  • Range age at sexual or reproductive maturity (female)
    1 to 2 years
  • Range age at sexual or reproductive maturity (male)
    1 to 2 years

Beyond the act of mating, both male and female Texas toads have no parental investment. (Lannoo, 2005)

  • Parental Investment
  • no parental involvement
  • pre-hatching/birth
    • protecting
      • male

Lifespan/Longevity

In the wild, the average lifespan of Texas toads is unknown. However, like most anurans, mortality is at its highest rate in the tadpole stage.

These toads are not often kept in captivity. However, anecdotal records from the Philadelphia Zoo showed that a once-wild Texas toad (adult at the time of capture) lived there for 4.25 years. (Bowler, 1977; Lannoo, 2005)

  • Range lifespan
    Status: captivity
    4.25 (high) years

Behavior

Texas toads are active at temperatures above 17 degrees C. Texas toads hibernate during colder periods, from about December to February. During hibernation, the toads will dig deep holes under vegetation. When mating season begins, male Texas toads will be aggressive in establishing territories. Fowler’s toads (Anaxyrus fowleri) in Virginia rarely traverse more than 100 m between non-breeding habitat and their breeding ponds. As Texas toads belong in thee same genus, it is likely that they migrate similar distances. Beyond these short distances from non-breeding to breeding sites, Texas toads do not migrate seasonally.

Texas toads typically are nocturnal, and they will eat and drink at night only. Once mating season begins male Texas toads will eat during the day so that at night, they can call. During the night, they will use a call at a frequency of 2.4-2.8 kHz (kilohertz) and 39-57 trills per second. Male Texas toads will use the call to attract the females. Males keep calling until females actually touch them. Only then do the males cease calling. The males will then use a grasping method called amplexus to attach to the female. Female choice seems to be based partly on pool size; females choose males calling from larger ponds over those from smaller pools (giving the tadpoles a longer time until pool desiccation).

Texas toads are social animals. They will swim and hop in the water with others of the same or different species. (Dodd Jr, 2013; IUCN SSC Amphibian Specialist Group, 2021; Kane and Leu, 2021)

Home Range

Texas toads' home range is unknown. (Lannoo, 2005)

Communication and Perception

In order to deter predators, Texas toads will secrete a thin layer of toxin across the dorsal side. This chemical, if ingested, can cause immediate respiratory failure in predators. The chemicals that make up the toxin are 5-hydroxytryptamine, dehydrobufoenine, and N-methyl-5-hydroxytrptamine.

Texas toads have a sense of smell and eyesight but only can see bright lights and figures. In water their sense of touch is used, as they can sense a predator coming up to 3.8 meters away. The motion of the water and the direction the water is moving it alerts the toads. They can use sight, touch, and chemical cues to forage.

When mating, male Texas toads will use a loud trill for 1.5 seconds at 1-second intervals. These calls will last for 20 minutes during suitable mating weather. They call in choruses. They can call during the night using a call at a frequency of 2.4-2.8 kHz (kilohertz) at 39-57 trills per second. Male Texas toads will use the call to attract the females. Once females make physical contact with a calling male, he will cease calling. The males will then use a grasping method called amplexus to attach to the female while mating. (Altig and McDiarmid, 2015; Dodd Jr, 2013; Goldberg, 2018; Lannoo, 2005)

Food Habits

As tadpoles, Texas toads are algivores. Juveniles and adults are insectivores. Juveniles opportunistically eat items like ants (Order Hymenoptera, Family Formicidae), beetles (order Coleoptera), and flies (Order Diptera). Adults have a wider diet that includes these items plus moths (Order Lepidoptera), cicadas (Order Homoptera), true bugs (Order Hemiptera), and crickets (Order Orthoptera). Non-insects include spiders, millipedes, and centipedes. They can feed in or near the water. They also may forage under streetlights, as their prey are attracted to the lights. (Dodd Jr, 2013; Hibbitts and Adams, 2015; Lannoo, 2005)

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods
  • Plant Foods
  • algae

Predation

The known predators of the Texas toads are boat-tailed grackles (Quiscalus major), predatory beetle larvae in the families Dytiscidae and Hydrophylidae, and yellow mud turtles (Kinosternon flavescens). These predators mainly will attack tadpoles that lack toxic defense mechanisms. When adult Texas toads are approached by a predator, they will secrete a thin toxin onto their dorsal side. These toxins have been identified as 5-hydroxytryptamine, dehydrobufoenine, and N-methyl-5-hydroxytrptamine. Multiple species of garter snakes (Thamnophis) can prey on adults, as they are more tolerant of toxins. (; Lannoo, 2005; Springer and Montaña, 2015; Altig and McDiarmid, 2015; Lannoo, 2005; Springer and Montaña, 2015)

Ecosystem Roles

Texas toads are algivores as tadpoles and insectivores post-metamorphosis. They are prey of snakes, turtles, and predatory beetle larva as tadpoles. Once the Texas toads metamorphose, they secrete toxins that will deter predators.

Parasites of Texas toads include myxozoans (a parasitic cnidarian; Myxidium serotinum) that will attach to the lining of a gall bladder and tapeworms (Distoichometra bufonis) that infect the liver and the gall bladder. (Lannoo, 2005)

Commensal/Parasitic Species
  • myxozoans (Myxidium serotinum)
  • tapeworms (Distoichometra bufonis)

Economic Importance for Humans: Positive

Texas toads are involved in the pet trade. In Texas, they are among the most collected amphibian species for the purpose of sale. Current sale prices in the United States are about $12. (IUCN SSC Amphibian Specialist Group, 2021; Lannoo, 2005; Prestridge, 2009)

Economic Importance for Humans: Negative

Texas toads can negatively affect the pets of humans with their toxins. The toads, if ingested, are poisonous and have the capacity to seriously sicken or kill pets. (Lannoo, 2005)

Conservation Status

Texas toads are listed as a species of "Least Concern" on the IUCN Red List. They have no special status on the US Federal List, CITES, and the State of Michigan List.

Threats to Texas toads include the use of pesticides and herbicides in nearby agricultural lands. The runoff into their breeding pools may cause harm or even death. Although not a direct threat, Texas toads may hybridize with Woodhouse's toads (Anaxyrus woodhousii). This could reduce the breeding pool in areas where the two species coexist.

Conservation measures for Texas toads are minimal, as their populations appear to be stable. Acknowledged threats have not seemed to decimate species numbers on a large scale. In Mexico, they are known to already exist in protected habitats and reserves. (IUCN SSC Amphibian Specialist Group, 2021; Lannoo, 2005)

Contributors

Janita Lyde (author), Radford University, Karen Powers (editor), Radford University, Victoria Raulerson (editor), Radford University, Christopher Wozniak (editor), Radford University, Genevieve Barnett (editor), Colorado State University.

Glossary

Nearctic

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.

World Map

acoustic

uses sound to communicate

bilateral symmetry

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.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

choruses

to jointly display, usually with sounds, at the same time as two or more other individuals of the same or different species

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

freshwater

mainly lives in water that is not salty.

herbivore

An animal that eats mainly plants or parts of plants.

hibernation

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.

indeterminate growth

Animals with indeterminate growth continue to grow throughout their lives.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

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).

metamorphosis

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.

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pet trade

the business of buying and selling animals for people to keep in their homes as pets.

poisonous

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).

polygynous

having more than one female as a mate at one time

saltatorial

specialized for leaping or bounding locomotion; jumps or hops.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

visual

uses sight to communicate

References

Altig, R., R. McDiarmid. 2015. Handbook of Larval Amphibians of the United States and Canada. Ithaca, New York: Cornell University Press.

Basset, L., M. Forstner. 2021. Geographic Distribution: USA, Texas, Wilson Co.: Bufo speciosus (Texas Toad). Herpetological Review, 52/1: 76.

Bowler, J. 1977. Longevity of reptiles and amphibians in North American collections. Herpetological Circulars, 6: 1-32.

Dayton, G., R. Jung, S. Droege. 2004. Large-scale habitat associations of four desert anuran in Big Bend National Park, Texas. Journal of Herpetology, 38/4: 619-627.

Dodd Jr, K. 2013. Frogs of the United States and Canada. Baltimore, Maryland: John Hopkins University Press.

Elliot, L., C. Gerhardt, C. Davidson. 2009. The Frogs and Toads of North America: A Comprehensive Guide to Their Identification, Behavior, and Calls. Boston, Massachusetts: Houghton Milfflin Harcourt.

Farr, W., D. Lazcano, P. Lavín Murcio. 2013. New distributional records for amphibians and reptiles from the state of Tamaulipas, Mexico III. Herpetological Review, 44/4: 631-645.

Galán, A., J. Light. 2017. Reptiles and amphibians associated with Texas pocket gopher (Geomys personataus) burrow systems across Texas sand sheets. Herpetological Review, 48/3: 517-521.

Goldberg, S. 2018. Reproduction of the Texas toad, Anaxyrus speciosus (Anura: Bufonidae) from Texas. Sonaron Herpetologist, 31/1: 2-4.

Hibbitts, T., C. Adams. 2015. Anaxyrus speciosus. Herpetological Review, 46/2: 210-212.

IUCN SSC Amphibian Specialist Group, 2021. "Anaxyrus speciosus" (On-line). The IUCN Red List of Threatened Species 2021: e.T54761A53950771. Accessed December 10, 2021 at https://dx.doi.org/10.2305/IUCN.UK.2021-3.RLTS.T54761A53950771.en.

Kane, M., M. Leu. 2021. "Frog migration in southeast Virginia" (On-line). Accessed December 15, 2021 at https://vsgc.odu.edu/wp-content/uploads/2021/11/Kane.pdf.

Lannoo, M. 2005. Amphibian Declines: The Conservation Status of Unites States Species. Los Angeles, California: University of California Press.

Lares, R., R. Martínez, H. Gadsden, G. León, G. Gaytán, R. Trapaga. 2013. Checklist of amphibian and reptiles of the state of Durango, Mexico. Journal of Species Lists and Distribution, 9/4: 714-724.

Olsen, C., A. Lovering, J. Carr. 1999. Alpha-melanocyte stimulating hormone and habituation of prey-catching behavior in the Texas toad, Bufo speciosus. Hormones and Behavior, 36/1: 62-69.

Olsen, C. 1998. Behavioral and Physiological Effects of Alpha-Melenocyte-Stimulating Hormone in the Texas Toad (Bufo speciosus) (Master's Thesis). Lubbock, Texas: Texas Tech University.

Prestridge, H. 2009. Amphibian and Reptiles Trade in Texas: Current Status and Trends (Master's Thesis). College Station, Texas: Texas A&M University.

Ramesh, R., K. Griffis-Kyle, G. Perry, M. Farmer. 2012. Urban amphibians of the Texas panhandle: Baseline inventory and habitat associations in a drought year. IRCF Reptiles & Amphibians, 19/4: 243-253.

Springer, L., C. Montaña. 2015. Morphological diversity and community organization of desert anurans. Journal of Arid Environments, 122: 132-140.

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