Squirrel sweets

Throughout New England, metal spigots are sticking out of tree trunks. It's sugaring season. When the sap flows, the buckets fill and the pots boil for hours to make maple syrup.

For unknown centuries humans have harvested this spring treat. But they weren't the first.

Since long before men rammed spiles into sugar maple bark, Red Squirrels have been making pre-spring rounds of these trees. They nip the bark, creating little grooves to start the sap dripping, and then move on to bite more bark. A day or two later, after the sap that flowed from the cuts has mostly evaporated, the rodents return to eat the sweet, sticky residue.

How do they know this cause-and-effect connection -- that a bite plus a wait yields food? The sap has barely any taste, yet these animals have learned to distill the watery fluid to its sweet essence -- squirrel-made maple syrup.

Will pancakes and butter be next?