Weird Nature The Most Poisonous Frogs & Toads  

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If you're like most people, you might walk up on a pretty frog or some toads and pick it up. Ok, most people probably wouldn't do that, which is a good thing seeing as some species of frog are some of the most toxic animals on the planet. What makes a toad or frog poisonous isn't the same as what makes a snake venomous. It has a lot to do with what they eat, but thanks to their particular biology, they have the ability to secrete poisons that can kill an adult human on contact!

The most poisonous frogs in the world that are considered deadly to humans are usually found in places you probably wouldn't run into them, but that doesn't mean you should go around hunting frogs. Many of these frogs are beautiful in coloring and look perfectly benign, but don't let their small stature and cute looks fool you, picking up a poisonous frog could very well be the last thing you ever do so take note of these little hoppers and respect the deadliest frogs on the planet.

Poison dart frog is listed (or ranked) 1 on the list The Most Poisonous Frogs & Toads
Photo: ucumari photography/flickr/CC-BY-NC-ND 2.0

Poison Dart Frogs are some of the most beautiful frogs on the planet, which is a shame as they are also the deadliest in the world. There are 170 species of Poison Dart Frogs found throughout northern and central South America, mostly in the Amazon Rainforest, which is where they got their name. They don't shoot little poison darts as their name implies, Amerindians used to use their toxic secretions on the tips of their blow darts making them particularly deadly.

They derive their toxicity due to their diet, which consists of ants, mites, and termites. In terms of toxicity, they secrete an ooze out of their backs, which comes in the form of a lipophilic alkaloid. The toxin is lethal to almost every animal on the planet except for the one predator species these frogs must contend with. The Erythrolamprus Epinephelus has developed an immunity to the toxin of Poison Dart Frogs and preys on them whenever possible.

Scientific Name: Dendrobatidae

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Greening's Frog is listed (or ranked) 2 on the list The Most Poisonous Frogs & Toads
Photo: Emmaantle/Wikimedia Commons/CC BY-SA 4.0
Greening's Frog

Greening's Frog is vastly different from other poisonous frogs in that it is venomous, somewhat like a snake. They are equipped with skull spines capable of injecting venom into other animals that might prey upon them. Not only are they dangerous to potential predators, they can inject their venom into humans who handle them and they are often seen headbutting prey so they can shoot their deadly poison into other animals.

These dangerous, spiny frogs are found throughout the desert Caatinga regions of Eastern Brazil where they live among the vegetation. Strangely, these frogs' venomous nature wasn't discovered until 2015, nearly 120 years after they were first described and they were discovered "the hard way" when a biologist received a shock while handling one. 

Scientific Name: Corythomantis greeningi

Bruno's Casque-Headed Frog is listed (or ranked) 3 on the list The Most Poisonous Frogs & Toads
Photo: Renato Augusto Martins/Wikimedia Commons/CC BY-SA 4.0
Bruno's Casque-Headed Frog

Bruno's Casque-Headed Frogs are small, deadly frogs found in the varying habitats of Brazil. They are known for their elongated snout, but also for their venom, which they can inject into their prey or potential predators via skull spines. This feature makes Bruno's Casque-Headed Frog similar in nature to the Greening's Frog, which is also endemic to Brazil.

The toxin of a Bruno's Casque-Headed Frog is incredibly potent and deadly. It has been compared to that of the fer-de-lance pit viper, also found in the region, but its toxicity is approximately 25 times as deadly. Like their venomous cousins, the Bruno's Casque-Headed Frog headbutts its intended prey or potential predators as a means of injecting their deadly venom. They can be dangerous to handle by humans and should be considered armed and dangerous.

Scientific Name: Aparasphenodon brunoi

Panamanian golden toad is listed (or ranked) 4 on the list The Most Poisonous Frogs & Toads
Photo: brian.gratwicke/flickr/CC-BY 2.0
Panamanian Golden Toad

As its name suggests, the Panamanian Golden Toad is endemic to Panama along the mountainous slopes in the west-central parts of the country. Unfortunately, it may no longer exist in those places as it is believed to have gone extinct in the wild in 2007. Fortunately, individuals captured for captive breeding programs have allowed the species to survive extinction, at least within the confines of zoos and laboratories.

The toxin of a Panamanian Golden Toad consists of a cocktail of deadly agents making this one of the deadliest toads in the Americas. A large-enough dose can kill within 20 to 30 minutes, through both convulsions and a disabling of both the circulatory and respiratory systems. Like other toads, their secretions are meant to deter predation.

Scientific Name: Atelopus zeteki