Ilha da Queimada Grande: Why Only Navy Soldiers & Vetted Scientists Can Land

Thirty-three kilometers off the coast of Itanhaém in São Paulo state, Brazil, the rocky rainforest of Ilha da Queimada Grande looks from a boat like an untouched tropical paradise. Yet Brazilian federal law strictly forbids any civilian boat from anchoring or landing on its shore.

Roughly 11,000 years ago, rising post-glacial sea levels flooded the land bridge connecting this hill to mainland South America. Trapped with no ground mammals left to hunt, the island’s population of Bothrops insularis—the golden lancehead pit viper—adapted to climb trees and strike migratory birds out of the air.

Because an avian target can fly out of reach in seconds after a strike, the golden lancehead evolved fast-acting hemotoxic and neurotoxic venom roughly three to five times more potent than that of its mainland relatives. Since the island’s lighthouse was automated in the 1920s, only Brazilian Navy maintenance crews and researchers certified by the Chico Mendes Institute (ICMBio) and Instituto Butantan are permitted to step ashore—always accompanied by a physician carrying specialized antivenom.