An accidental discovery on a nighttime walk led one scientist and his team to wonder: How many mammals glow under ultraviolet light? The list keeps growing, but scientists still aren’t sure why these furry creatures glow. For more, go to http://vox.com/unexplainable It’s a great place to sign up for our newsletter, view show transcripts, and read more about the topics on our show. Email us at unexplainable@vox.com. We read every email! Also, we are conducting an audience survey to better serve you. It takes about five minutes, and it really helps out the show. Please take our survey here: vox.com/survey Support Unexplainable by making a financial contribution to Vox! bit.ly/givepodcasts Learn more about your ad choices. Visit podcastchoices.com/adchoices