 Many animals have a specific temperature range where they are active , meaning the times they are active vary with the seasons . Snakes and lizards hibernate during the winter months , are diurnal during the late spring and early fall , and become crepuscular during the heat of summer . Many insects and some birds also alter their times of activity . Some animals , like ground squirrels and marmots , have one or more periods of estivation , a summer hibernation that allows them to avoid the hottest and driest periods . 
