Harris Center for Conservation Education

This time of year makes me hungry. The brisk air of autumn sets my stomach growling. I'm not alone in this. Don't you feel it, too? I am starving as the earth turns towards fall. During this season, we are busy eating at harvest festivals, apple-picking parties, pumpkin spice everything, and a holiday dedicated to candy consumption. Instead of fighting this autumnal hunger, let's embrace and recognize its wild roots. We are, after all, mammals, and although we like to think we are far different than our wild kin, our extra-seasonal hunger at this time of the year is a reminder that whatever else we are, we are still animals at the core. Research has shown that we do actually eat more and want to eat more in the fall than at any other time of year. We are hard-wired to pack it on before winter arrives. Our bodies know just what to do. It all has to do with darkness. The increasing length of nighttime hours triggers hormonal responses in the endocrine system that cue us into eating more. We are packing our larders full, so to speak, before the scarcity of winter arrives. This evolutionary adaptation has helped us survive many winters, including the last ice age. We share this survival adaptation with other wild animals. Think of black bears, for example. At this time of year, black bears fill their bellies with as much food as possible. From late summer through mid-October, bears enter a stage known as hyperphagia, characterized by excessive eating and drinking, allowing them to fatten up healthily before entering their winter resting stage. They go from consuming about 5,000 calories a day in the spring and summer to eating 20,000 calories daily during hyperphagia, increasing their weight by 20 to 30 percent. To accomplish this eating marathon, black bears spend about twenty hours a day feeding during this seasonal stage. They are racing against time to gain enough weight before winter sets in. They seek out high-protein foods, such as beechnuts, acorns, and walnuts, while consuming late summer and early fall fruits rich in sugars, including blackberries, blueberries, apples, and choke cherries. As generalist omnivores, a black bear's diet in NH is 80 percent plant matter, while the other 20 percent comprises insects, especially colonial insects like ants, and other animals, including carrion (dead animals).The bounty of autumn nuts, high in protein and rich in fat, is essential to a bear's winter survival. Instead of waiting for the acorns or beechnuts to drop, bears climb up these trees and harvest the high-value food before it falls to the ground to be readily consumed by other hungry animals, such as deer, turkey, mice, chipmunks and squirrels. Bears find a sturdy place to hold their weight in the tree and then bend and break the nut-laden branches, pulling them towards them. They take one nut off at a time to eat using their paws, lips, and tongue. They carefully bite it, separating the nut from its case, while pushing the hard, indigestible out of their mouth, similar to how we might eat sunflower seeds. When they are done, they jam the branches underneath themselves. These giant piles of branches in nut-bearing trees are called bear nests. Look for them once the trees lose their leaves in November. Often, you can also find bear claw marks on the tree, leaving a visual and scent-marked message to other bears in the area. There are years when the wild nut crop is prolific and synchronized, meaning all the oak trees across North America simultaneously have a banner year for seed production. Scientists refer to this phenomenon as a mast year. In an average year, oak trees produce about 2,000 acorns, but the number jumps to 10,000 during a mast year. Mast years are good news for bears and other wildlife dependent on these high-protein foods. Wildlife populations, including chipmunks, mice, blue jays, turkeys, deer and bears, will often increase, demonstrating that when ample resources are available, wildlife reproduction and survival rates increase.