Nutrients are rapidly transferred from the nuts into the new seedlings. Gray squirrels bite off the pointed acorn tips, which prevents sprouting and loss of food value. The acorn therefore keeps better as a future food source. White and bur oak acorns, which are sweeter and thus consumed first, consist of about six percent proteins and sixty-five percent carbohydrates. Red oak acorns have a higher fat and tannin content.
Tannins are bitter tasting chemicals that can interfere with digestion.
Since all oaks contain tannins in their leaves and acorns, those with higher amounts of tannin are less attractive to herbivores. Squirrels bury red oak acorns in the forest floor where rain and snow gradually lessen the tannin content over winter. In spring the nuts are fit to eat and also able to sprout. Wood ducks forage heavily on white oak acorns before beginning their fall migration. Deer also favor the nutritious nuts.