Amphibians
Surinam Horned Frog
Ceratophrys cornuta · also called Surinam horned frog, Amazonian horned frog, South American horned frog
The Surinam horned frog is built around one idea: a mouth. Squat, spiky-browed, and nearly as wide as it is long, it buries itself in the Amazon leaf litter and ambushes anything unlucky enough to wander close — frogs, mice, snakes, even other horned frogs.
Overview
Surinam horned frogs live in rainforest leaf litter near slow water and temporary pools across the Amazon Basin and Guiana Shield. Females reach 12–13 cm and are extremely heavy-bodied, mottled brown and green, with a huge head and gape. Fleshy “horns” above each eye break up the outline among dead leaves.
The ambush
Buried with just the eyes and mouth showing, the frog strikes explosively at anything that passes, trying to swallow prey nearly its own size — sometimes with fatal results for the frog if the meal is too big.
Cannibals from birth
Adults will eat smaller horned frogs, including their own species, and the tadpoles are predators too, attacking and eating other tadpoles, siblings included, in a shrinking pool.
Status
The Surinam horned frog is Least Concern, widespread across its Amazonian range, though collected for the pet trade.
Surinam Horned Frog: common questions
Why is it called a horned frog?
Each upper eyelid carries a soft, fleshy, pointed projection that sticks up like a small horn, and in profile the pair of them, together with the frog's angular jawline, gives an overall spiky, almost demonic look. The horns are not hard or used as weapons; their real function is camouflage, breaking up the round outline of the eye and head so that a Surinam horned frog sitting motionless among dead leaves reads as just another curled, pointed leaf rather than as an animal, which matters a great deal for an ambush hunter that relies entirely on staying undetected until prey wanders within striking range.
How big a prey can a horned frog eat?
Remarkably large ones relative to its own size. Horned frogs of the genus Ceratophrys, including the Surinam horned frog, have an enormous gape and a wide, muscular mouth, and they will attempt to swallow other frogs, lizards, small snakes, and rodents that are a substantial fraction of their own body length and weight, sometimes nearly as large as the frog itself. This aggressive appetite is not always successful; there are documented cases of horned frogs dying after choking on prey too large to swallow or being injured by a struggling victim, since the frog’s strategy is simply to strike first and figure out the swallowing afterward.
Do Surinam horned frogs really eat each other?
Yes, cannibalism is common at every life stage. Adults show little restraint about attacking and swallowing a smaller horned frog of their own species if it comes within range, which is one reason captive keepers must house them individually rather than in groups. The tadpoles are just as aggressive — they are active predators rather than typical algae-grazing tadpoles, and in a crowded temporary pool they will attack, kill, and eat other tadpoles, including their own siblings, especially when food is scarce or the pool is shrinking. This cannibalistic streak is thought to help a few tadpoles reach metamorphosis quickly by removing competitors before the pool dries out completely.
Are Surinam horned frogs good pets?
They are popular in the amphibian hobby, valued for their striking looks and their bold "sit and wait" behaviour, and captive-bred animals, including some colour morphs from related horned frog species, are widely available. They are relatively easy to keep, needing a simple enclosure with damp substrate to burrow into, a shallow water dish, and appropriate live food, and they do not need to climb or have much space since they barely move. The main cautions are that they can and do bite hard if a hand is mistaken for food, so feeding with tongs is recommended, and they must always be kept alone because of their cannibalistic tendencies.