The world’s most toxic creatures

Bold and beautiful yet highly poisonous, these amazing amphibians may be small but they can kill in seconds

Frogs and toads lack defensive weapons such as claws or teeth, instead relying on their ability to escape by jumping or by being very still and well camouflaged. However, if fleeing or hiding doesn’t work, some of them have a secret weapon: poison. Many secrete toxins from glands in their skin, which protect them from bacteria growing on their permanently damp skin as well as making them taste bad to predators.

Poison dart frogs, however, take this ability to produce toxins to the extreme, with three species in particular – the golden dart frog, black-legged poison dart frog and the kokoe poison dart frog – being lethal. These three Colombian species are undoubtedly the most poisonous vertebrates on the planet. The beautiful yet deadly little frogs are so named because the poison that they excrete is rubbed onto the tip of blow-pipe darts used by native South American hunters.

There are more than 170 different species of poison dart frogs, each one a member of a vibrant and varied family that sports a rainbow of colours and patterns. Perhaps the most well-known frogs in the world, their bright displays are a clear advert to predators of their deadly potential.

1. Diet

Insects make these frogs deadly

Poison dart frogs are carnivores and their unappealing diet of insects – mostly ants and beetles – produce high levels of powerful, concentrated toxins in their skin. The more deadly varieties of poison dart frogs can be seen in zoos the world over, although the levels of toxins in captive dart frogs is far lower than their wild counterparts as their diet of crickets, fruit flies and aphids is less toxic than the insects they would naturally feast on.


2. Boldness

These amazing amphibians are small but mighty

The bold colours of poison dart frogs serve as a stark warning to anyone that dares to get too close – touch a golden poison dart frog and you could be dead within minutes. The common names of the dozens of different species of poison dart frog offer a clue to their striking identities – it’s little surprise that the bumblebee dart frog is yellow and black, for instance. But there is a huge variety in the colours and patterns sported by these frogs, and one single species can in fact display a wide range of different colour morphs, including the golden poison.


3. Poison

The deadly toxin with no known antidote

Poison dart frogs have evolved to produce highly poisonous skin secretions because many of their predators, such as snakes and spiders, have evolved to develop a resistance to milder toxins. Their young are a brownish colour and their poison has not developed yet – these animals accumulate their poison as they reach adulthood. In fact, one adult frog contains sufficient poison in its skin to kill at least ten adult humans.

The poison is absorbed directly through the skin and is easily transmitted. Its potency and the ease with which it is administered make it even more deadly. It attacks the nervous system and quickly leads to heart failure. A single genetic mutation in these frogs means they are entirely immune to their own toxins.


4. Location

Look but don’t touch!

These endangered frogs are native to rainforests in the remote lowlands of Colombia, existing in an increasingly small area of Pacific coastline. Researchers often
need to travel very far along tropical rivers to access their habitats, a long way from towns that might offer emergency medical treatment should it be needed. The remoteness of golden dart frogs in itself makes them even more deadly as speedy treatment would be very difficult to receive before the poison took hold.

Words: Lucy King