The below description is taken from LEGO.com.
"Me build, therefore me am!"
This would-be inventor from the prehistoric past is always tinkering with sticks, rocks and the occasional bricks he finds lying around, trying to invent something new. Of course, everything he comes up with has already been invented - he's a Caveman with a tiny little brain, after all - but that doesn't stop him from trying. He never gets jokes and usually needs things explained to him with gestures and pictures…and even then, he gets it wrong most of the time.
The Caveman is very strong and always hungry. If something looks like it might be food, he'll try to take a bite, and if it runs away, he'll lift his club up above his head and chase it down. Not a lot of people know it, but he's also an excellent artist who can create incredible landscapes and murals using only the simplest of tools!