The island is the only natural home of the critically endangered, venomous Golden lancehead pit viper (Bothrops insularis), which has a diet of birds.

The ensuing evolutionary pressure allowed the snakes to adapt to their new environment, increasing rapidly in population and rendering the island dangerous to public visitation.

Rain forest covers 0.25 square kilometres (62 acres) of the island, with the remaining area consisting of barren rocks and open grassland.

However, several sources have rejected this claim[clarification needed] and stated it is simply impossible to support such a large population with so few resources.

[citation needed] Despite a population of 41 recorded bird species on Queimada Grande, the golden lancehead (Bothrops insularis) relies on only two: the Troglodytes musculus (southern house wren), which is usually able to avoid the golden lancehead as a predator; and the Chilean elaenia (a species of flycatcher), which feeds on vegetation in the same area as the snake.

[citation needed] Because of the overall low population of the golden lancehead, the snake was labelled critically endangered on the IUCN Red List of Threatened Species.