Because they are wild hickory nuts.
This year, the oaks and hickories are going crazy, and producing bumper crops, apparently it's another mast year. We (well mostly Georgia), have been removing buckets of acorns from our driveway. A few places along my walk to the beach with Skye are overhung by large Hickory trees which also are producing tremendous amounts of fruit:
|A hickory nut still in the husk
I'm not sure, but I think most of our hickories are Mockernut Hickories. The fruits are similar to walnut or black walnut or even a pecan (Pecans are really a type of hickory), and have a thick husk, which splits into
5 4 parts, and releases the nut. In one place along the walk you can just pick up the nuts laying along the street, both in and out of the husks in huge numbers:
|One pocket's worth of nuts, washed, and with the floaters (bad nuts) removed.
The nuts themselves are incredibly thick shelled and hard, and are very difficult to crack. I bent a traditional nut cracker trying, checked on line, and found people using special home made nut crackers, or hammers. A little experimentation showed than an ordinary vice-grip does a satisfactory job:
|A cracked hickory nut
The shell is very intricate inside, and the nut meat is not especially easy to extract whole. The meat looks, and tastes very much like walnut, although it has a stronger taste, and a hint of vanilla. Instructions are to dry them for a month before cracking them; I hope that will help the meat shrink away from the shell and make it easier to extract.
|The meat extracted from one nut
I have quite a pile of nuts drying in the basement. In a month, I'll get serious about it, and try to extract at least enough meat to make a batch of brownies with.
Wait for it: