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Paws For Thought: Darwin's Frog

Who? Darwin’s frog and the Chile Darwin’s frog.

Where? Darwin’s frog (Rhinoderma darwinii) lives in the temperate forests and streams of south and central Chile and Argentina, where it was discovered in 1834 by Charles Darwin (surprise surprise!) during his voyage around South America in the Beagle. It’s cousin, the Chile Darwin’s frog (Rhinoderma rufum), is native specifically to Chile and is suspected to be virtually extinct.

Why am I interested? Ranging from a dark chocolatey brown to a piercing green, our little friends only measure in at about three centimetres each, and yet we've got five facts here which prove that the best things really do come in small packages... prepare for a truly ribbet-ing read!

Darwin's frog
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Introducing Darwin's frog

1) Bizarre baby-sitting

Given that it only applies to a small number of special amphibians and fish, we can forgive you if the word mouthbrooding leaves you scratching your head. Put quite simply, the tadpoles grow in the vocal sacs of the males and, horrifyingly enough, the father quite literally has to vomit up his young. After the female has laid her eggs on moist ground, the male swallows the clutch and keeps his offspring warm, cosy and incubated in his vocal sac. Once the tadpoles have metamorphosed into froglets, the father regurgitates them into water where they continue their adolescence in a more conventional manner - talk about an overprotective parent!

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Frogs usually lay their frogspawn and leave the tadpoles to develop alone

2) The sapito vaquero

Not content with being one of the most camera-shy of amphibians, these elusive creatures also go under another alias, the sapito vaquero, or the cowboy frog. No one knows exactly what earned them this swaggering nickname, but one suggestion is that their call sounds similar to that of a rancher when herding his cattle.

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These frogs are the cowboys of the amphibian world

3) Predator prevention

These artful amphibians know how to react in a sticky situation and that when it comes to staying alive sometimes it’s better to be... erm, dead. When danger comes knocking they instinctively roll over onto their backs, looking to all the world like another leaf carpeting the forest floor, and have even been known to dive into the water in a bid at self-preservation, floating motionless on their backs and playing dead.

Well camouflaged
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Their leaf-like appearance is an excellent camouflage

4) An uncertain future

Sadly the infamous chytrid fungal disease, which has ravaged amphibian populations the world over, might be lurking at the root of the worryingly declining numbers of Darwin’s frogs. This vicious fungus stops important substances being transferred through the frogs’ skin, eventually leading to their death. Deforestation and the resulting loss of habitat could also be partially to blame, however, and scientific researchers from the Universidad Andrés Bello in Chile and the Zoological Society of London are still working hard to explain why Darwin’s frog might be edging its way towards extinction.

Fire salamander
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The Netherlands fire salamander population has been wiped out by the fungus

5) Still hope for the Chile Darwin’s frog?

Living as we do in a world of ubiquitous CCTV cameras, Facebook check-ins and GPS, the idea of disappearing sounds like the work of a wand-waving magician, of a scheming criminal mastermind or... well, of the unassuming Chile Darwin’s frog actually, which has not been spotted since the late 1970s. Unlike Darwin’s frog, it releases its tadpoles from the vocal sac before they become froglets. It cannot be known for certain whether it is completely extinct or not, and some experts have not completely given up hope - so don’t forget to keep your eyes peeled for these masters of disguise just in case!

Chilean forest
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The forest has lots of frog-friendly nooks and crannies to hide in

If this has sparked your interest in the unsung heroes of the Chilean wildlife scene, why not make like Darwin’s frog and hop over here to meet some more of our enigmatic characters?