Ilha da Queimada Grande, also known as Snake Island, is an island off the coast of Brazil in the Atlantic Ocean. It is administered as part of the municipality of Itanhaém in the State of São Paulo. The island is small in size, only 43 hectares (106 acres), and has a temperate climate. The island's terrain varies considerably, ranging from bare rock to rainforest.
Nickname: Snake Island
|Area||430,000 m2 (4,600,000 sq ft)|
|Highest elevation||206 m (676 ft)|
|State||State of São Paulo|
|Administered by||Chico Mendes Institute for Biodiversity Conservation (ICMBio)|
The island is the only natural home of the critically endangered, venomous Bothrops insularis (golden lancehead pit viper), which has a diet of birds. The snakes became trapped on the island thousands of years ago following the end of the last ice age when rising ocean levels disconnected the island from the mainland. 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.
Queimada Grande is closed to the public in order to protect both people and the snake population; access is available only to the Brazilian Navy and selected researchers vetted by the Chico Mendes Institute for Biodiversity Conservation, the Brazilian federal conservation unit.
Located approximately 33 kilometres (21 mi) off the coast of the state of São Paulo, Brazil, the island is approximately 430,000 square metres (110 acres) in area. The island ranges in elevation from sea level to 206 metres (676 ft) above sea level. The island has a temperate climate that is similar to that of its neighbouring island Nimer. 0.25 square kilometres (62 acres) of the island is covered by rain forest; the remaining areas consist of barren rocks and open grassland. Queimada Grande ranges from an average of 18.38 °C (65.08 °F) in August to 27.28 °C (81.10 °F) in March, and rainfall ranges from 0.2 millimetres (0.0079 in) per month in July to 135.2 millimetres (5.32 in) in December.
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" is Portuguese for “forest fire” – when locals attempted to clear land for a banana plantation on the island, they attempted to clear rain forest with fire. A lighthouse was constructed in 1909 to steer ships away from the island. The last human inhabitants left the island when the lighthouse was automated.
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. It is blocked off to the public to protect human and snake life.
Because there are so many snakes on one island — by some estimates one snake to every square meter (10.8 square feet) — there is competition for resources. 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.
The island was previously 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 number 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 golden lancehead 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.
- Marques, Otavio A. V.; Kasperoviczus, Karina; Almeida-Santos, Selma M. (2013). "Reproductive Ecology of the Threatened Pitviper Bothrops insularis from Queimada Grande Island, Southeast Brazil". Journal of Herpetology. 47 (3): 393–399. doi:10.1670/11-267. S2CID 86639586.
- Thomas, Emily (July 4, 2014). "Brazil's 'Snake Island' Is The Place Of Nightmares, We're Pretty Sure". Huff Post Science. TheHuffingtonPost. Retrieved October 24, 2015.
- "Exposição traz história da ilha que abriga única espécie de cobra no mundo" (DOC) (in Portuguese). Secretaria De Comunicação Social, Prefeitura Municipal De Itanhaém. 2007. Retrieved 2016-09-20.
- Cox, Savannah (December 17, 2012). "Four Tiny Islands That You'll Never Visit". all-that-is-interesting. PBH network. Retrieved November 4, 2015.
- Channel, Discovery. "Treasure Quest: Snake Island Facts".
- Marques, Otavio, A. V.; Martins, Marcio; Sazima, Ivan (2002). "A jararaca da ilha da Queimada Grande" (PDF). Ciência Hoje (in Portuguese). Sociedade Brasileira para o Progresso da Ciência. 31 (2): 56–59. Retrieved 8 August 2015.
- Snake Island Part 1, Vice
- ARIE das Ilhas Queimada Pequena e Queimada Grande (in Portuguese), ISA: Instituto Socioambiental, retrieved 2016-11-20
- "Snake Island – Ilha da Queimada Grande". AtlasObsura. Atlas Obscura. November 11, 2015. Retrieved October 28, 2015.
- Martins, Marcio; Sawaya, Ricardo J.; Marques, Otavio A. V. (2008). "A First Estimate of the Population Size of the Critically Endangered Lancehead, Bothrops insularis". South American Journal of Herpetology. 3 (2): 168–174. doi:10.2994/1808-9798(2008)3[168:AFEOTP]2.0.CO;2.
- Marques, Otavio A. V.; Martins, Marcio; Develey, Pedro F.; Macarrão, Arthur; Sazima, Ivan (2012). "The golden lancehead Bothrops insularis (Serpentes: Viperidae) relies on two seasonally plentiful bird species visiting its island habitat". Journal of Natural History. 46 (13–14): 885–895. doi:10.1080/00222933.2011.654278. S2CID 53357655.