You're probably familiar with many of the common categories scientists use for animals: warm-blooded or cold-blooded, nocturnal or diurnal. But what about the animals that don't fit in? Sharks cannot be classified as warm or cold-bloodedÑthey are somewhere in-between. And Eurasian eagle owls don't hunt during the day or night. Instead, they swoop through the trees at dawn and dusk. Author and science educator Jessica Fries-Gaither introduces seven common categories scientists use and the animals that break those rules.