Step 1 : Introduction to the question "Which of these mammals has bioluminescent fur?"
...The platypus is one of the planet's most extraordinary creatures. Despite being mammals, these Australian natives lay eggs and possess venomous spines on their rear legs. They also have tails resembling those of beavers and bills similar to ducks, which they use to sense prey while hunting at night with their eyes closed. Adding to their list of peculiar traits, scientists have recently discovered that platypuses have bioluminescent fur. When exposed to ultraviolet (UV) light—a spectrum invisible to the human eye—their fur emits a blue-green glow.