Pine resin is pretty amazing stuff. I once made pine pitch glue out of pine sap chunks I collected, and it's amazingly strong for something that's not available at Home Depot. ;) You could easily mistake it for epoxy. From what I remember, I basically melted the sap and mixed in some ground dried grass and a little bit of ash. I honestly forget what exactly it was that I was gluing, though. At one point I was making an atlatl, so maybe it was for that.

As an aside, pine sap is also an amazing fuel in its liquid state. Once it gets going, it burns like gasoline. They're natrue's waterproof fire starters, and as there were neanderthals who used fire, I imagine they might have used pine sap to help start them.