how do squirrels crack nuts?

Answer 1

Doesn't say how they crack them, I'd say they just chew the nuts.

Squirrels like to eat nuts and seeds. That's why they live near trees such as oak, walnut, hickory, and maple. They also look for pine cones and other seeds, berries, grain, mushrooms, insects, small animals, and spring buds and flowers on trees and shrubs. Because squirrels will eat baby birds, you might see birds squawking at squirrels near their nests.

Squirrels stash nuts in hollow trees and under fallen leaves. Gray and fox squirrels spend a lot of time digging holes and burying single nuts and acorns in the ground. During the winter they sniff out the acorns and dig them up to eat. Naturalists have seen squirrels dig through a foot of snow to find a cache of nuts. Of course, the squirrels miss some nuts, and in this way they help plant the next forest.