Darrin Lunde worked for more than twenty years as a mammalogist at the American Museum of Natural History and is now the collection manager in the Division of Mammals at the Smithsonian's National Museum of Natural History in Washington, DC. He's written several books for children, including the Theodor Seuss Geisel Honor book Hello, Bumblebee Bat, as well as Whose Poop Is That?; Whose Footprint Is That?; Hello, Baby Beluga; and Meet the Meerkat.

Kelsey Oseid illustrated Whose Poop Is That? and Whose Footprint Is That? She received her BA with honors in Visual Communications from Loyola University Chicago. She works in both traditional and digital media and often mixes the two to create her illustrations. www.kelzuki.com