KLK1 and hyperinsulinism: Together, our integrative single-cell study indicates that Jamaican fruit bats evolved many diabetic-like features to deal with their diets but evolved protective mechanisms that prevent disease, such as upregulation of KLK1 in type A intercalated cells in the kidney, which protects against diabetic tissue damage74, and downregulation of IRS1 in beta cells in the pancreas, which causes hyperinsulinism but not diabetes144.