Ceratophrys cornuta is a striking frog due to the presence of its large mouth that is approximately 1.6 times wider than the length of the body. Adult females are larger (up to 120 mm and 130g) than adult males (up to 72 mm and 60g). (Duellman and Lizana, 1994). Color patterns are variable greens, browns, and beige with darker streaks of greens and browns. The ventral side shows a light colored body with uniform dark pigmentation on the throat (Lynch 1982). Like other members of the genus, C. cornuta possesses heavy calcification, ornamentation, casquing, and a hyperossified cranium. The skull is strong and akinetic, with all bones but the premaxilla, columellae, and the septomaxilla fused. A pronounced interocular crest characterizes this species. Other autapomorphies include the absence of a carina from the zygomatic region to the maxilla below the eye, the absence of vomerine teeth, pointed tubercles on flanks, smooth face, extensively webbed outer toes, and a slender, elongated tubercle on eyelids. (See Wild (1997) for detailed osteology).

C. cornuta are widely distributed in terra firma and inundated rainforest areas in the Amazon Basin. They prefer the leaf-litter habitat associated with their cryptic coloration and burrowing habits (Duellman and Lizana 1994).

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 (Native )

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).

Range length: 7 to 15 cm.

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

• Terrestrial
• Freshwater

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 ; terrestrial ; freshwater

Terrestrial Biomes: forest ; rainforest

Aquatic Biomes: lakes and ponds; rivers and streams; temporary pools

Wetlands: marsh

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).

Animal Foods: mammals; amphibians; reptiles; fish

Primary Diet: carnivore (Eats terrestrial vertebrates, Piscivore )

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.

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

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 ; acoustic

Other Communication Modes: choruses

Perception Channels: visual ; tactile ; acoustic

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).

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).

Range lifespan

Status: captivity: 15 (high) years.

Average lifespan

Status: captivity: 10 years.

Average lifespan

Sex: female

Status: captivity: 10.3 years.

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

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).

Breeding interval: Amazon horned frogs breed once every year.

Range number of offspring: 300 to 600.

Range time to hatching: 3 to 25 days.

Range time to independence: 0 (low) minutes.

Range age at sexual or reproductive maturity (female): 3 to 4 years.

Range age at sexual or reproductive maturity (male): 3 to 4 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); 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)

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.

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: least concern

Duellman and Lizana (1994) estimated an average abundance of 1.9/ha in an Amazonian Peruvian site. Adult activity is mostly nocturnal, while juveniles were found to be active during both day and night. C. cornuta burrows the posterior end of its body with lateral movements of the hind legs and rear part of the body, maintaining its cryptically colored head above the leaf-litter. This species are avid feeders, employing a sit-and-wait ambush tactic on leaf-litter dwelling arthropods (mostly ants and beetles), and large prey (other frogs, small reptiles, and small mammals). Stomach content analysis found that large prey could account to more than half the volumetric content of an adult’s diet (Duellman and Lizana 1994).

Limited field observations have been made of C. cornuta breeding behavior. Breeding seems to occur after heavy rainfall, especially at the start of the rainy season (around November). Males call with a loud "baaaaa." The tadpoles have a bluntly rounded snout, eyes in a dorsolateral position, a sinistral ventrolateral spiracle with an ovoid opening facing posteriorly. The mouth parts are highly keratinized, with several rows of teeth and a beak. The larvae have tan colored bodies with a greenish yellow belly and a tan colored translucent tail. Like their adult counterparts, the larvae are voracious carnivores. Their diet consists mainly of other tadpoles (Duellman and Lizana 1994).

C. cornuta has the widest distribution within the Ceratophrys genus and is not classified as endangered by the IUCN Red List.

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)

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

Known commercially as horned frogs or pac-man frogs, ceratophryids are popular in the pet trade due to their atypical gapes and voracious appetites. However, C. cornuta is a less common pet than C. ornata and C. cranwelli.