Whiptail lizards bolt in straight lines across the desert floor.
Side-blotched lizards start and stop in zigzag routes. To defend their territory, many lizards do push-ups. Nelson's knowledge of lizards comes from more than just reading a pile of wildlife textbooks. She's spent hours watching them as part of her work with Mark Andersen, a wildlife scientist with NMSU's Agricultural Experiment Station . The researchers are studying how human disturbance affects lizard populations.