Here’s another chapter from my new book, Ten Million Aliens.

The golden poison frog is probably the most poisonous creature on earth. Chickens and dogs have died from contact with a paper towel on which this frog has walked. It’s found only in Colombia, and it’s tiny: a little scrap of charming, elegant yellow death. Its skin is drenched in batrachotoxins, alkaloid poisons that prevent nerves from transmitting impulses. Come into contact with the stuff and you die of heart failure. Not that the frog is particularly anxious to come into contact with you: the poison is entirely for self-defence. The frogs are a decent size for poison arrow frogs, reaching 55mm or a couple of inches in length, and they carry a single milligram of poison. This is enough to kill 10,000 mice, 20 humans or two African bull elephants. Death comes within minutes.

Inevitably, these fearsome creatures play a significant role in human cultures. The Choco Emberà Indians use them to poison the darts they use for hunting. Gently brush the tip of your dart or arrow on the back of a living frog; you can do and should do this without harming the frog. You then have a weapon that will be deadly with a mere scratch, and will remain so for two years. Word of advice: handle these weapons calmly.

Because of all this history, this danger, this charisma, these frogs have become much desired by frog collectors. It’s dangerous for an animal to be greatly hated by humans, but it can be just as dangerous to be greatly loved. The best survival strategy is to be ignored. The golden poison frog has suffered because its loving collectors have taken it from the wild without any thought for how the wild frogs will survive. Many populations have died out as a result. The frogs lives in primary rainforest in Colombia, and so inevitably, they are also suffering from the destruction of their habitat. They have a rather patchy distribution across an area of less than 250 square kilometres of rainforest on the Pacific coastal plain: it’s a lot less than it sounds and it doesn’t sound much to start with.

This frog has also suffered from one of the great contradictions of wildlife: peace is a bad thing. The area in which the frogs live is a great deal more secure than it has been in recent years; as a result, people are moving about more freely. Gold-miners are moving in, illicit coca cultivation is on the rise and timber companies are likely to move in at any second. All this is the worst of news for the golden poison frogs: you can’t, alas, poison a bulldozer, not even with a paper towel. We have reached a state in which the animal that has developed the most effective bit of protection in the entire history of the earth is now dismayingly vulnerable. It is completely unprotected by law.

In 2010 the Colombian conservation organisation ProAves  launched a series of expeditions in search of remaining populations of the frog. They found to their dismay that it was no longer on any of its known traditional sites; it took extraordinary exertions before five tiny populations were identified. They are now in the process of identifying the right areas to create the first protected areas for the golden poison frog, and are doing this with the support of the World Land Trust, a partner organisation in Britain that has agreed to fund the land purchase.

Astonishing: we are on the edge of wiping out one of the most extraordinary and thrilling creatures on the planet. No matter how well a creature is protected by nature and by evolution, it is always vulnerable to us humans. There’s nothing we can’t do when we put our minds to it. Still, at least we are now beginning to put our minds to saving the golden poison frog: we’d be much poorer without such a creature to give us nightmares.

The poison dart frogs, or to be more technical, the Dendrobatidae, are a bewildering bunch: bizarre, beautiful, deadly. Most could sit comfortably on your thumb-nail, though such an arrangement may not be so comfortable for you. They come in a glorious range of colours and patterns because they need to be seen. Their lives depend on their ability to stand out from their surroundings. No point in being lethally unappetising unless you tell people: after all, if they discover it for themselves it’s too late for you. This is called aposematic colouration, and no creature adopts this tactic more stylishly. Each shining frog looks as if it has just been painted in Airfix paints and has yet to dry. It’s not clear what makes them so poisonous, though it’s probably something to do with diet – at any rate, they lose their toxicity in captivity. There are 175 species, and they’re all toxic in different degrees. It is one of the great paradoxes that the wild world occasionally goes in for: let’s not bother hiding. Let’s tell the whole world we’re here, let’s shout our identity as loud as we can: and then we’ll be safe. These fragile little specks of colour are so powerful only a bulldozer can hurt them.