The Venomous Pit Vipers of Brazil’s Deadly Snake Island

bothrops-insularis-dangerous-snake-island (Image: Otavio Marques)

Ilha da Queimada Grande is an island off the coast of Brazil. Not far off the state of Sao Paulo, and separated from the mainland by several miles of ocean, it’s home to the largest concentration of deadliest snakes in the world.

Between 2,000 and 4,000 golden lancehead vipers call the rocky, 43-hectare island home, and they’re unbelievably dangerous. A single bite can kill an adult in less than an hour, and the island is firmly entrenched in the lore and legend of Brazil. Folktales tell of those who have dared to land on Ilha da Queimada Grande – and these stories almost invariably end in death.

There’s a lighthouse on the island, and for decades the only human inhabitants were those who manned it. That ended, though, when they reportedly all met their demise at the fangs of Snake Island’s eponymous serpents. Over time romantic stories claiming the snakes were put there deliberately to guard long-buried pirate treasure became enshrine in local myth. But as Smithsonian Magazine reports, the truth is far less fantastic.

bothrops-insularis-dangerous-snake-island-2 (Image: ABC News via YouTube)

When Snake Island was cut off from the mainland by rising water levels around 11,000 years ago, the snakes began to evolve and adapt to their changing territory. With no prey on the ground, they needed to be able to hunt in the air. And since birds are their main source of food, they developed the highly potent venom capable of dropping their prey where they struck.

Officially known as Bothrops insularis, golden lanceheads are endemic to Ilha da Queimada Grande. They’re rough-scaled, yellow-brown appearance with faint markings running down their fairly short bodies distinguishes them from other creatures. The highly-venomous snake detects its prey by its heat signature, and when it’s ready to strike, its hollow fangs fold out from where they’re stored against the top of its mouth.

Because of its singular habitat, the snakes are listed on the IUCN Red List as Critically Endangered. The ominously-named Snake Island is now protected, but in the past, much of it was cut and burned, destroying much of the golden lancehead’s native habitat. The serpent has also been plagued by poachers (see video below.)

Today – and considering the potent predators lying in wait – Ilha da Queimada Grande has a surprising number of visitors. In addition to military personnel who regularly perform maintenance on the old lighthouse, the island is a popular destination for biologists and other researchers studying one of the world’s deadliest snakes and how it evolved. Sensibly, those visiting Brazil’s Snake Island are required to do so in the presence of a doctor – just in case.

Related – The Surprisingly Common Adder: Fact & Folklore of Britain’s Only Venomous Snake


About the author: Debra Kelly




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