Biofluorescence refers to an organism's ability to absorb ultraviolet light (UV) and emit it as a colorful glow. The skill has been documented in fish, amphibians, reptiles, birds, and even microscopic tardigrades. However, glow-in-the-dark mammals are still new to science. They currently include just a handful of nocturnal animals such as flying squirrels, opossums, and platypuses. The latest to hop on to this elite list is a jumping rodent called the springhare.