Actually, labs are known eaters as they are bred to be "mouthy".
As the hunting dog that RETRIEVES birds and other prey for its masters/mistresses, it just has that intrinsic LOVE of something in the mouth!

As for my previous Pups (at RB now), Sid (a huge black dobe cross) was the WORST.
Once when his recall was weak and I was stupid, I attempted to get him to come to me with a diaper in his mouth..A dirty diaper. Someone had changed their baby on the beach and left it there! I did finally get...well half of it back.
Also, he loved Kleenex/tissues out of the garbage.
Once, in the midst of company, he lovingly brought down a used condom from the bin beside my bed and proceeded to lay down and gnaw it. Then imagine my embarrassment as I had to carry said item to garbage in full view of guests.
After that, I got wise, and did the right thing...Dogproofed my home like I would a child.
From the sounds it, you should all do the same!
