LOL poor Jacob, working for 7 long years with a persistent boner. No wonder he humped the first thing that came along.

@dlee878 -- obviously, people didn't bumble around in pitch darkness before the invention of electricity. They had fires and oil lamps and stars and the moon. There would've been enough light to notice a difference, especially if he'd been in love with Rachel for so many years. He'd know her shape, the way she walked, what she smelled like, tone of voice. When a man 'marries' a woman (in that culture), he gets to see the goods, so to speak -- face, hair, all the other bits -- on the wedding night.