Noah finally beaches the ark after the flood. He released all the pairs of animals, saying "Go forth and multiply!"
Coupla months later he thinks to check up on the animals. Finds there are lots of baby animals all round the place. Except the two snakes. Still only two of them. Asks the snakes what the problem is. They say "well can you chop down some trees for us to live in?" So Noah does just that.
Three months later he checks again. Baby snakes everywhere!! He calls Mum and Dad snake over and asks them what fixed the problem. Their reply?
"Well, 'sobvious innit? We're adders. We need logs to multiply..."

Nah, I didn't laugh much either...