<P> Ilha da Queimada Grande has a variety of vegetation . The island is partly covered in rainforest and partly bare rock and grassy cleared areas, a result of deforestation . The deforestation is the origin of the island's name: the term "Queimada", in Portuguese, means to burn because when locals attempted to clear land for a banana plantation on the island, they had to clear rainforest using this technique . A lighthouse was constructed in 1909 to steer ships away from the island . The last human inhabitants left the island when the lighthouse was converted to being automated . </P> <P> The island and the Ilha Queimada Pequena to the west are protected by the 33 hectares (82 acres) Ilhas Queimada Pequena e Queimada Grande Area of Relevant Ecological Interest, created in 1985 . The Brazilian Navy has closed the island to the public and the only people who are allowed on the island are research teams who receive waivers to collect data . </P> <P> Because there are so many snakes on one island, by some estimates one snake to every square meter of the island, there is competition for resources . Despite a population of 41 recorded bird species on Queimada Grande, the golden lancehead relies on only two: the Troglodytes musculus (the southern house wren), which is able to avoid the golden lancehead as a predator, and the Elaenia chilensis (a species of flycatcher), which feeds on vegetation in the same area as the snake . The island was thought to have a population of about 430,000 snakes, but recent estimates are much lower . The first systematic study of the population of the golden lancehead found the population to be 2,000 to 4,000, concentrated almost entirely in the rainforest area of the island . This might have happened because there was a limited amount of resources and the population became level, but in 2015 an estimate by a herpetologist on a Discovery Channel documentary stated that the population remains at 2,000 to 4,000 golden lanceheads . The Bothrops insularis also may be at risk from inbreeding, effects of which are evident in the population . Because of the overall low population of the golden lancehead, the snake was labelled critically endangered on the IUCN Red List of Threatened Species . It also was placed on the list of Brazil's endangered animals . The island is also home to a smaller population of Dipsas albifrons, a non-venomous snake species . </P>

How many snakes are there on snake island
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