Nut Case

I have long been fond of having a bowl of nuts-in-the-shell and dipping into it to crack open and enjoy.

The other day, I came across an odd walnut. Usually, a walnut shell has two halves (each one of which can make for a fun sailboat).

This walnut, shown on the left, has a shell with three parts. For comparison, a normal walnut is shown on the right.

Has anyone else ever seen one of these anomalies? I'm a bit reluctant to crack it open. Could this be a new walnut defense mechanism? If so, its working for me.