Animals that are most active at dawn and dusk, when temperatures are cooler than mid-day, are called crepuscular. The subdued morning and evening light helps make them less visible to predators, but is bright enough to allow them to locate food. Some animals are crepuscular mainly because their prey is also. Crepuscular animals include mule deer, coyotes, porcupines, mountain cottontails, jackrabbits, and many songbirds.