Forbidden Snake Island: Where Snakes Evolved Differently

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There are quite a few islands around the world which have come to be known as “Snake Island” but of all these, Brazil’s Ilha da Queimada Grande is perhaps the most notorious because it is not only infested with snakes that have caused the government to close down the island to the public, it is further the only home to one of the most venomous snakes in the world- the Golden Lanceheads.

Brazil’s Ilha da Queimada Grande
(Left) A golden lancehead viper (photo by Nayeryouakim) and (right) Brazil’s Ilha da Queimada Grande (photo by Prefeitura).

Ilha da Queimada Grande is easily accessible as it is located in the Atlantic Ocean just 33 kilometers off the coast of Brazil’s São Paulo and is approximately 430,000 square meters in area.

Brazil’s Ilha da Queimada Grande is popularly known as “Snake Island” because the island is full of snakes. It is the only place in the world where Golden Lanceheads, a species of pit vipers, are found. Because of the snakes, despite only being 33 kilometers off the coast of Brazil’s São Paulo, it has been closed to the public.

Since Snake Island is the only place in the world where the Golden Lanceheads are found, they have been categorized as critically endangered by the International Union for Conservation of Nature (IUCN). One of the reasons to not allow people on the island is also to protect this particular species of snake. It is estimated that there are as many as 4,000 Lanceheads present on the island.

However, it is being observed that the population of the species is falling and inbreeding is speculated to be one of the reasons for that.

Besides Golden Lanceheads, another species that has made the island their home is the Dipsas albifrons- a non-venomous snake species.

There are about 4,000 Golden Lanceheads present on the island today. Because of their low population, the species has been categorized as critically endangered by IUCN. Inbreeding is believed to be one of the reasons for the falling population. Dipsas albifrons- a non-venomous snake species is also found on the island.

According to a predominant theory, the Lancehead vipers were not always this venomous. About 11,000 years ago, the island used to be connected with the mainland, but due to rise in sea levels, the island was cut-off and the vipers there got trapped. This led to limited food sources for the snakes and migratory birds appeared to be a solution to the issue. But the problem was that the venom of the snakes would take time to bring the birds down and often by the time the venom would act, the birds would fly away somewhere else and many a time outside the island. The snakes needed stronger venom that would work instantly and over the thousands of years the Lanceheads evolved differently comparing to other vipers and now and they are five times more venomous comparing to their mainland cousins. They have grown so venomous that the venom can now even melt flesh.

According to a theory, about 11,000 years ago when the island was cut off from the mainland due to rising sea levels, the vipers were trapped on the island where there wasn’t much food. So the snakes evolved over the thousands of years in a different way and became five times more venomous to kill their prey, which mostly includes birds, instantly.

Golden Lanceheads are named so because of their pale yellowish color and pointy head. On average, they grow about 70 centimeters but can grow as long as 118 centimeters. It mostly feeds on migratory birds as the local birds are too familiar with the moves of the Lanceheads, but reportedly, the snakes can also consume lizards and other snakes.

Though the island is now closed to the public, it has perfect conditions for human settlements and actually, it did have a reasonable human occupation in the past but it was eventually vacated because of the snakes.

Golden Lanceheads are named so because of their yellowish color and pointy head. They on an average grow about 70 centimeters. Lanceheads mostly feed on migratory birds but are also reported to feed on lizards and other snakes. There also used to be a human settlement on the island.

In fact, the name Ilha da Queimada Grande roughly translates to “slash and burn fire or big burnt island” because at one point of time there was an effort made to begin a banana plantation there and deforestation had taken place, but the plan didn’t really take off.

The last human who left the island was the lighthouse operator when the lighthouse was automated. It was constructed in 1909. There is an unconfirmed but popular story that the snakes had made their way into the lighthouse one night when the operator and his family were asleep and they had to flee. Later, their bodies were recovered from different parts of the island.

Ilha da Queimada Grande roughly translates to “slash and burn fire or big burnt island.” It is called so because, at one time, the island was burned to prepare it for a banana plantation. The last person to leave the island was the operator of the lighthouse after it was automated. According to unofficial stories, the snakes had attacked the operator and his family.

Another such story that is not officially confirmed is of a tragic fisherman whose boat broke down and he was stranded on the island. He didn’t know where he had landed and ventured deep into the forest. He but did manage to return to the boat but was bitten already and collapsed on his boat.

In another story, a stranded fisherman ventured into the forest and was bitten by the snakes. To protect the humans and snakes, only Brazilian Navy and scientists are now allowed on the island. However, poachers do try to make their way into the island to capture Golden Lanceheads as they are highly paid for in the black market.

The island is now a completely restricted area and only Brazilian Navy and selective scientists are allowed to land, but despite all the restrictions and all the dangers, poachers have been known to enter the island illegally in pursuit of Golden Lanceheads which can fetch as high as USD 30,000 in the black market.


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