Ceratophrys cornuta

Geographic Range

Amazon horned frogs, Ceratophrys cornuta , are found in the Amazonian Basin of Colombia, Ecuador, the Guianas, Venezuela, Peru, Bolivia, and Brazil (IUCN, Conservation International, and NatureServe, 2004).

• Biogeographic Regions
• neotropical neotropical
  • native native

Habitat

Amazon horned frogs occur in open areas within the forest (IUCN, Conservation International, and NatureServe, 2004). They are found within the leaves on the forest floor (Project Amazonas Inc., 2003). Horned frogs are terrestrial and reside near freshwater marshes and pools within old forest areas (IUCN, Conservation International, and NatureServe, 2004).

• Habitat Regions
• tropical tropical
• terrestrial terrestrial
• freshwater freshwater

• Terrestrial Biomes
• forest forest
• rainforest rainforest

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

• Wetlands
• marsh marsh

Physical Description

These frogs are fairly large, ranging from 7 to 15 centimeters in length (Staniszewski, 1995). The body is very round and the head is prominent (Project Amazonas Inc., 2003). Color of males can range from tan or lime to dark green. Sometimes, males display all of these colors simultaneously, whereas females are usually just tan (Bartlett and Bartlett, 2003). The ventral surface of these frogs is gray (Staniszewski, 1995; Duellman, 1978). The limbs are short and exhibit dark bands of coloring (Bartlett and Bartlett, 2003; Duellman, 1978). The thighs are colored brown with faint yellow spotting (Duellman, 1978). The body exhibits small pointed warts, and the mouth is white (Staniszewski, 1995). Females of this species are larger, and the males have nuptial pads on the toes of the front feet (Staniszewski, 1995). The most distinguishing feature of this species is the presence of horns above the eyes (Bartlett and Bartlett, 2003; Duellman, 1978; Staniszewski, 1995).

• Other Physical Features
• ectothermic ectothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger
• sexes colored or patterned differently
• male more colorful

Development

After fertilization, the eggs take anywhere from 3 to 25 days to hatch (Huitt, 2003). Once the tadpoles hatch from their eggs, they take about 90 days to metamorphose (Staniszewski, 1995). After metamorphosis, the tiny frogs are from 1 to 1.3 centimeters in length (Staniszewski, 1995).

• Development - Life Cycle
• metamorphosis metamorphosis

Reproduction

Mating is started when the males call to the females, and once two are paired the eggs are put onto the back of the female by the male. Mating appears to be polygynous. (Huitt, 2003)

• Mating System
• polygynous polygynous

Amazon horned frogs mate seasonally (Zug, Vitt, and Caldwell, 2001). They reach sexual maturity at around 3 to 4 years of age (Staniszewski, 1995). These frogs mate in ephemeral pools and, compared to the size of the adults, the number of eggs they deposit is very minimal at about 300 to 600 eggs (Bartlett and Bartlett, 2003). Mating is initiated when the males call to females. Once two are paired, the eggs are put onto the back of the female by the male (Huitt, 2003). Finding an appropriate place for the offspring to develop is the duty of the female, and hatching occurs sometime between 3 and 25 days after fertilization (Huitt, 2003).

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

The main forms of parental care provided in this species are provided by the female. In addition to supplying eggs with an adequate food supply for development of the young, the mother frog selects a safe place to deposit her eggs after they have been fertilized. After depositing the eggs in a safe location, male and female Amazon horned frogs have no parental involvement with their offspring. There is high mortality in the young, so that although many eggs are laid, not many offspring survive.

• Parental Investment
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • protecting
    • female

Lifespan/Longevity

Little is know about the lifespan of C. cornuta in the wild, but in captivity they have fairly long lives. Captive individuals reach an average age of 10 years (Max-Planck-Gesellschaft, 2005). A maximum lifespan of 15 years has been recorded in captivity (Staniszewski, 1995).

Behavior

Ceratophrys cornuta is nocturnal, coming out only at night in order to avoid the excessive warmth of the day (Huitt, 2003). A notable behavior of these frogs is the way that they capture prey. Horned frogs bury themselves in the leaves on the ground with only the head sticking out. Hidden in this manner, an individual waits for something edible to pass by--at whcih time it strikes (IUCN, Conservation International, and NatureServe, 2004).

These frogs can be violent when fully grown (Staniszewski, 1995). They are solitary, and a male will defend his territory violently (Huitt, 2003).

• Key Behaviors
• terricolous
• nocturnal nocturnal
• motile motile
• sedentary sedentary
• solitary solitary
• territorial territorial

Home Range

The size of the home range of these frogs is not known.

Communication and Perception

When trying to find a potential mate, communication is mostly acoustic. When males are together in a group, they exhibit a noisy bleating sound (Bartlett and Bartlett, 2003). During mating itself, some tactile communication is undoubtedly important.

When feeding, these frogs bury themselves in the substrate and wait for the motion of passing prey (Bartlett and Bartlett, 2003; IUCN, Conservation International, and NatureServe, 2004). In this instance, their main mode of perception is visual.

• Communication Channels
• tactile tactile
• acoustic acoustic

• Other Communication Modes
• choruses choruses

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic

Food Habits

Amazon horned frogs are ravenous predators, having large mouths and long teeth to help them eat prey (Zug, Vitt, and Caldwell, 2001). They are considered "wait-and-ambush" hunters because they bury themselves in the substrate with only their faces outside the ground (Bartlett and Bartlett, 2003; IUCN, Conservation International, and NatureServe, 2004). Once in this position, C. cornuta eats almost anything that passes, as long as it will fit in the frog's mouth (Project Amazonas Inc., 2003). They have been known to feed on mice, fish, and tadpoles of their own species (Huitt, 2003). They also eat other smaller frogs (Huitt, 2003; Project Amazonas Inc., 2003).

• Primary Diet
• carnivore carnivore
  • eats terrestrial vertebrates
  • piscivore piscivore

• Animal Foods
• mammals
• amphibians
• reptiles
• fish

Predation

The cryptic coloration of these frogs is thought to be an anti-predator adaptation as it aids in camouflaging them in their surroundings (Huitt, 2003; Project Amazonas Inc., 2003). It is also thought that the horns may function as part of this camouflage, since the horns may be perceived by predators as the stem of a leaf or other such object (Project Amazonas Inc., 2003).

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Ceratophrys cornuta preys upon many small animals, such as rodents and frogs, and serves as prey for larger animals. Beyond these relationships, little is known about the role of these frogs in their ecosystem.

Economic Importance for Humans: Positive

One benefit of this species for humans is its availability in the pet trade. Their strange look and their violent appetites make them favorable pets for herpetologists (Project Amazonas Inc., 2003).

• Positive Impacts
• pet trade pet trade

Economic Importance for Humans: Negative

These frogs do not actively seek to harm humans, but they do have very sharp teeth and can bite hard if not handled carefully (Bartlett and Bartlett, 2003).

• Negative Impacts
• injures humans
  • bites or stings

Conservation Status

Althought C. cornuta is listed as least concern by the IUCN Red List, actions of humans may still have adverse affects on this species. Population numbers may be affected through the pet trade, since the majority of those sold are being taken directly from the wild (IUCN, Conservation International, and NatureServe, 2004; Project Amazonas Inc., 2003). Drops in population numbers may be avoided by stopping the collection of this species from the wild and making only captive-bred specimens available as pets.

Additional Links

AmphibiaWeb

Encyclopedia of Life

Contributors

James Harding (editor, instructor), Michigan State University, Lyndsay Richards (author), Michigan State University , Nancy Shefferly (editor), Animal Diversity Web.

References

Bartlett, R., P. Bartlett. 2003. Reptiles and Amphibians of the Amazon . Florida: University Press of Florida.

Cochran, D. 1955. Frogs of Southeastern Brazil . Washington, D.C.: Smithsonian Institution Press.

Duellman, W. 1978. The Biology of an Equatorial Herpetofauna in Amazonian Ecuador . Kansas: University of Kansas Museum of Natural History.

Huitt, M. 2003. "WhoZoo Project" (On-line). Accessed May 05, 2005 at http://www.whozoo.org/Intro2002/MattHuitt/MDH_Amazonhornedfrog.html .

Staniszewski, M. 1995. Amphibians in Captivity . New Jersey: T.F.H. Publications, Inc..

Zug, G., L. Vitt, J. Caldwell. 2001. Herpetology . San Diego: Academic Press.

IUCN, Conservation International, and NatureServe. 2004. "Global Amphibian Assessment" (On-line). Ceratophrys cornuta - Amazonian Horned Frog. Accessed February 01, 2005 at http://www.globalamphibians.org/servlet/GAA?searchName=Ceratophrys+cornuta .

Max-Planck-Gesellschaft. 2005. "Longevity Records" (On-line). Accessed May 04, 2005 at http://www.demogr.mpg.de/longevityrecords/ .

Project Amazonas Inc. 2003. "Project Amazonas Inc." (On-line). Accessed January 31, 2005 at http://www.projectamazonas.com/subpages/floraandfauna/FloraFaunaGalleries/amphibians-tropical%20frogs%20gallery.htm .