Desert rose tree (Adenium obesum sokotranum) in a coastal landscape. This subspecies of the desert rose is endemic to the Socotran archipelago of islands, meaning that it is found nowhere else. Usually, it has a thick, bottle-shaped trunk to conserve water and provide stability, but in sheltered areas it can grow tall and slender. The islanders traditionally use the poisonous bark of the desert rose to kill small fish for bait. Socotra is located in the Indian Ocean at the mouth of the Gulf of Aden, 340 kilometres (km) from mainland Yemen and 250km from the coast of Somalia. Its isolation has led to the evolution of a unique flora and fauna.