Madagascar is an island lying off the southeastern coast of Africa. It is the world's fourth largest island. Madagascar split from Africa during the Early Jurassic, around 180 million years ago, and split from the Indian subcontinent around 90 million years ago, allowing native plants and animals to evolve in relative isolation. Consequently, approximately 90 percent of all plant and animal species found in Madagascar are endemic, including the lemurs. The combination of southeastern trade winds and northwestern monsoons produces a hot rainy season (Nov-Apr) with frequently destructive cyclones, and a relatively cooler dry season (May-Oct). Rain clouds originating over the Indian Ocean discharge much of their moisture over the island's eastern coast; the heavy precipitation supports the area's rainforest ecosystem.