Cameroonian ‘horror’ frog breaks own bones to claw off attackers!
The Spanish saying “Cuando las ranas críen pelo” translates roughly as ‘when frogs grow hair’ – a phrase similar to the English ‘pigs might fly’ – meaning something that is very unlikely to happen. Incredibly, this curious amphibian doesn’t only grow hair-like tendrils, but also – remarkably – has the ability to intentionally break its own bones as a means of unleashing a sharp claw from its feet to repel predators! When frogs grow hair, indeed…
Native to the highland streams of the Cameroon in West Africa, the hairy – or ‘horror’ – frog (Trichobatrachus robustus) is prized by local hunters as a tasty delicacy, eaten roasted whole over a fire. However, hunters have learnt to use long spears and machetes to hunt this formidable frog, keeping well out of reach of its razor-sharp claws.
When threatened, this adaptable amphibian tenses the muscles in its hind feet, causing a claw – very similar in shape to a cat’s claw – to break free from the foot bone to pierce the frog’s toe. A cunning defence mechanism, the frog’s ability to pierce its own skin parallels the Wolverine-like ability of a previously featured curiosity, the Spanish ribbed newt, to develop ingenious means of foiling would-be predators. Indeed, the British travel writer and explorer Gerard Durrell wrote with pained accuracy about the pointed success of the hairy frog’s claws in drawing his blood in The Bafut Beagles.
However, it is yet to be discovered how the frog retracts the claw after being threatened – if it is retracted at all. Amphibians generally have excellent abilities to rapidly regrow skin over healing wounds, so the production of the claw is unlikely to be more than a minor inconvenience to the frog.
During the breeding season, male hairy frogs develop hair-like strands of skin called papillae. These curious flowing locks allow the frog to breathe for longer underwater – a process called cutaneous respiration – when guarding unhatched eggs.
Another incredible amphibian for the Cabinet of Freshwater Curiosities, with endlessly fascinating and inventive adaptations to its environment.
Find out more from:
- Wikipedia page
- New Scientist report
- Science blogs
- Blackburn et al (2008) paper “Concealed weapons: erectile claws in African frogs” in Biology Letters
- IUCN Red List details
- Encyclopedia of Life
- Amphibia Web
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