No one had spotted the world’s smallest known snake for nearly two decades. Some scientists worried that maybe the Barbados threadsnake had become extinct. But Connor Blades lifted a rock in a tiny forest in Barbados and held his breath one sunny morning. The project officer with the eastern Caribbean island’s environment ministry had already spent more than a year looking for the snake. The species can fit comfortably on a coin. The specimen in front of him was too tiny to identify with the naked eye. So he analyzed it several hours later in front of a microscope at the University of the West Indies. And it was a Barbados threadsnake.