What is it like to be a bat? To sleep upside down, eat insects and use sound to ‘see’? Philosophers have debated the question for decades as a way to think about other minds, and bat ecologists have turned their tools towards it. One woman knows better than all of them. Fiona Gameson had both eyes removed because of a rare childhood cancer. She uses echolocation to navigate and see with sound. “I call it my 'bat sense',” she says.