Hibernation the summer months is aestivation. Often associated with low temperatures, the function of hibernation is to conserve energy when sufficient food is unavailable. To achieve this energy saving, an endothermic animal decreases its metabolic rate and thereby its body temperature. Hibernation may last days, weeks, or months depending on the species, ambient temperature, time of year, and the individual's body condition. Before entering hibernation, animals need to store enough energy to last through the duration of their dormant period, possibly as long as the entire winter. Larger species become hyperphagic, eating a large amount of food and storing the energy
History of the San Fernando Valley the location of human settlements in the San Fernando Valley was constrained by two forces: the necessity of avoiding winter floods and need for year-round water sources to sustain communities through the dry summer and fall months. In winter, torrential downpours over the western-draining watershed of the San Gabriel Mountains entered the northeast Valley through Big Tujunga Canyon, Little Tujunga Canyon, and Pacoima Canyon. These waters spread over the Valley floor in a series of braided washes that was seven miles wide as late as the 1890s, periodically cutting new channels and reusing old ones, before sinking into the gravelly