6th Grade · Science · Reading Passage · shared by Luke Morgan
Free 6th Grade Science reading passage: explore animal hibernation, metabolic depression, and energy conservation in bears to survive winter.
Imagine sleeping through an entire winter, not just for a few nights, but for many months. This incredible feat is exactly what some animals do through a process called hibernation , entering a deep sleep to survive cold weather and times when food is very scarce. Researchers are very interested in how these animals manage such a long rest without eating or drinking. Scientists often study black bears to understand their amazing ability to conserve energy, carefully monitoring a bear's heart rate and internal temperature throughout the long winter season.
One of the most important changes during hibernation is called metabolic depression , where the bear's body slows down almost all of its normal functions and uses much less energy. Its heart rate drops dramatically, often from 40-50 beats per minute to 8-10 beats. Breathing also becomes much slower and shallower, sometimes with long pauses between breaths. This allows the bear's body to survive solely on stored fat for many months. This deep resting state helps the bear save strength until warmer weather returns.
Another key change involves the bear's body temperature during hibernation. While many smaller hibernators, like woodchucks, let their body temperature drop significantly, bears are different. A hibernating black bear's body temperature usually stays around 88-93 degrees Fahrenheit, only dropping a few degrees. This controlled temperature drop is still enough to significantly reduce its energy needs. The bear relies on its thick fur and layers of fat to stay warm inside its den as it sleeps deeply.
These incredible physiological changes are about energy conservation . Before winter, bears eat a lot of food to build up thick layers of fat. This stored fat acts like a fuel tank, providing all the energy the bear…