The sci-fi story of a killer toad

The Avenger apprehends the suspect, before interrogating.

Claudio, Andrew and I are driving 40 minutes out of Santiago, Chile to investigate reports of a killer toad. This mass murderer, known to eat his victims AND their babies, has been on the run for decades, his rampage unabated. Meet Xenopus, the African clawed toad, one of the chief baddies in the global amphibian crisis.

With a name straight out of Star Trek and the looks to match, you couldn't design a freakier bad guy. From the Frankenstein stitches down his back to his fat, flat body and blank, bug-eyed stare. With no tongue, no ear drums and no eyelids, Xenopus is oblivious to evil. Not even his mother loved him - and would have gladly gobbled him up at the slightest sign of a food shortage. 

We arrive at a large rural estate and meet with our eye-witness, Jurgen, who hands us a bag of tadpoles and a bucket of toads. He tells us his property has been infested with alien amphibians since 1978. With obvious emotion in his voice, he laments that 2 years after the toads arrival he had his first "silent spring", completely absent of the much-loved chirrupy sing-song of the native frogs. So he went searching for them in places that were previously carpeted with frogs or inky black with tadpoles and found nothing. They had gone. Apparently forever. Jurgen suspects they may have been eaten by this new found foreign frog.

 

Among the species lost to Jurgen is the super cool four-eyed frog which boasts fake eyes on its bum to intimidate would-be predators. Try staring that one out.

We examine Jurgen's catch and confirm the suspect as Xenopus. Jurgen wants to know what African clawed toads are doing in Chile. Well, its quite a tale of human misadventure. Xenopus might look evil, but as usual our exploits put a bug-eyed Frankenstein toad in the shade. 

The African clawed toad is something of a scientific superstar. It all started in the 1930's when scientists discovered that Xenopus could be used as the world's first reliable pregnancy test. Yes you heard that right. No, Xenopus doesn't turn blue if you pee on it. But apparently if you inject a female toad with a pregnant woman's wee within 24 hours she will start laying eggs. 

The toad test replaced the far less reliable rabbit test and had the added advantage that the toad didn't die and could be re-used! I'm not sure if they sold home testing kits (the mind boggles) but the toad test reigned supreme as the most effective pregnancy test well into the 60's. Amazing but true. 

 

I just want to know how the hell the scientists found out? Did someone wee on one by accident? Or was it something altogether more sinister.

Anyway, the end result was that Xenopus were bred in their millions, exported to labs all around the world and went on to become the most studied amphibian on the planet. A model for biological research, Xenopus was the first vertebrate to be cloned and even went into space. 

Xenopus has been de-coded, re-built, documented inside and out but the one thing that scientists didn't discover until it was too late is that this globe-trotting toad doesn't travel alone. When it left Africa it took another of the local residents with it - the deadly Chytrid fungus - which it carries on its skin without being infected. 

All of which would be fine if the toads had just stayed in the lab, but clearly they didn't. For instance when the little blue strip finally replaced the toad as the pregnancy test of choice, millions were released into the wild all around the world, taking the fungus with them and spreading it to native frog populations which lacked immunity. 

Claudio tells Jurgen that the Xenopus infesting his property are thought to be yet another of Pinochet's crimes. Shortly after the military junta took over the airport in 1973, a consignment of Xenopus arrived by plane. Not accustomed with what to do with them, the military let them loose and they can now be found as far as 300 km's from the capital. 

We take the toads back to the lab and swab them for Chytrid. If they test positive, which other Xenopus found in the area have, then it might be that Jurgen's precious four-eyed frog will never be seen on his farm again. Because once the fungus gets in the local water system it is currently impossible to eradicate, making re-introduction of native frogs pointless. That is, until we find a cure. Something which needs more money and more research. So, if you feel like supporting Claudio and Andrew in their work then visit the EDGE website and donate money to them by clicking here.

Comments

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Well, As I returned from a Southern Hemisphere holiday, where temperatures were nearly 40 degrees C, I was shocked by the unusually cold weather in the UK. The winters in the UK are usually much milder than this as we all know, so what is going on with the weather? If you don’t know already, read on to find out and to read 10 top tips on driving safely during the snow period.

In most winters, especially in the past 20 years or so, winds reaching the UK normally came from the south-west. This meant the air had travelled over the relatively warm Atlantic and we got mild conditions in the UK. However, over the past three weeks the Atlantic air has been ‘blocked’ and cold air has been flowing down from the Arctic or the cold winter landmass of Europe (Met Office) of course.

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When I was pregnant I has the same feelings about that, so be patient.

[Amphibian Avenger]

James, thanks for the comment and thanks for reading!

[James Webley]

Nice post on the dreaded Xenopus, Kerry @ Save the Frogs was raving about them the other day!

[Lucy Cooke]

You're traumatised! Think how the frog felt...

[Bindu]

This is fascinating stuff, but I clicked on the chimp/frog link and I am completely traumatised....