<P> 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 . </P> <P> Several animals are unique to Craters of the Moon and the surrounding area . Subspecies of Great Basin pocket mouse, American pika, yellow - pine chipmunk, and yellow - bellied marmot are found nowhere else . Lava tube beetles and many other cave animals are found only in the lava tubes of eastern Idaho . </P> <P> In May 1980 wildlife researcher Brad Griffith of the University of Idaho started a three - year study to mark and count the mule deer in the monument . The National Park Service was concerned that the local herd might grow so large that it would damage its habitat . Griffith found that this group of mule deer has developed a drought evasion strategy unique for its species . </P> <P> The deer arrive in the southern part of the pre-2000 extent of the monument mid-April each year once winter snows have melted away enough to allow for foraging . Griffith found that by late summer plants in the area have already matured and dried to the point that they can no longer provide enough moisture to sustain the deer . In late July after about 12 days above 80 ° F (27 ° C) and warm nights above 50 ° F (10 ° C) the herd migrates 5 to 10 miles (8.0 to 16.1 km) north to the Pioneer Mountains to obtain water from free - flowing streams and shade themselves in aspen and Douglas - fir groves . Rain in late September prompts the herd to return to the monument to feed on bitterbrush until snow in November triggers them to migrate back to their winter range . This herd, therefore, has a dual summer range . It is also very productive with one of the highest fawn survival rates of any herd in the species . </P>

Craters of the moon national monument & preserve idaho united states