A farmer and his wife were lying in bed one evening; she was knitting, he was
reading the latest issue of Animal Husbandry. He looks up from the page and says
to her, "Did you know that humans are the only species in which the female
achieves orgasm?" She looks at him wistfully, smiles, and replies, "Oh yeah?
Prove it." He frowns for a moment, then says, "O.K." He then gets up and walks
out, leaving his wife with a confused look on her face. About a half an hour
later, he returns all tired and sweaty and proclaims, "Well I'm sure the cow and
sheep didn't, but the way that pig's always squealing, how can I tell?"
