2) Snake Island
Snake Island is an island off the coast of Brazil in the Atlantic Ocean. The island is small in size, only 43 hectares (106 acres), and has a temperate climate.
Its terrain varies considerably, ranging from bare rock to rainforest. The island is the natural home of venomous Bothrops insularis and Pit vipers. The snakes became trapped on the island thousands of years ago following the end of the last ice age. 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. The island is also home to a smaller population of ‘Dipsas Albifrons’. Because of the overall low population of the golden lancehead, the snake was labeled critically endangered on the IUCN Red List of Threatened Species. The island was previously thought to have a population of more than 430,000 snakes.