buds, leaves, stems, sprouts, and in some cases, the sap and storax of pine and sweetgum. When herbaceous plants are actively growing, they make up much of the beaver's diet. In the winter, beavers switch to woody plants and the food they have stored over the winter. The protein to calorie ratio of a beaver's diet is 40 mg/calorie in summer and 8 mg/calorie for the rest of the year. In northern latitudes, the water lilies Nymphaea and Nuphar are the most important herbaceous component. The rhizomes are stored in the food cache and remain actively growing. Willow is an important protein source and is likely to be available for the longest period of time in a beaver's habitat especially in the far north. When available, aspen and poplar are preferred over willow. Conifers are also cut or gnawed by beavers, and used for food and/or building material. Beavers do not necessarily use the same trees as construction material and as food. Inedible material is more likely to be used as the cap of a beaver family's food cache, the upper part which is frozen in the ice, while the cache itself is composed of edible, high quality branches, which remain unfrozen and accessible. Beavers avoid red maple, which can be the only tree left standing at the edges of some beaver ponds. The beaver's gut microbiome is complex and specialized for a wood-heavy diet, sharing a number of similarities with other mammalian herbivores. However the microbial community in the beaver shows less taxonomic diversity than the "typical" mammalian gut. The major OTUs are Bacteroidota and Bacillota. Predators Common natural predators include coyotes, wolves, and mountain lions. American black bears may also prey on beavers if the opportunity arises, often by smashing their paws into the beavers' lodges. Perhaps due to differing habitat preferences, grizzly bears were not known to hunt beavers in Denali National Park, Alaska. Less significant predators include wolverines, which may attack a rare beaver of up to adult size, and Canada lynx, bobcats, and foxes (predators of kits or very sick or injured animals, rather than full-grown beavers due to their increasingly smaller size). American alligators, which only minimally co-exist in the wild with beavers, also seldom threaten them. Both golden eagles (Aquila chrysaetos) and bald eagles (Haliaeetus leucocephalus) may on occasion prey on a beaver, most likely only small kits. Despite repeated claims, no evidence