Part of the show Dentistry & Teeth
Scientists studying birds in Norway have made an unusual discovery - successful males budget their sperm by shunning their old partners. The bird watchers expected the behaviour of male Great Snapes to match that seen in nightclubs, with the males taking every opportunity to mate. This would ensure that they father as many offspring as possible. However, after mating, the male birds wouldn't touch their partner with a bargepole if she approached again, and even used violence to chase her away. This type of bird has a strong pecking order, with a few "pop-star" males getting the most sex. The scientists thinks that these lucky few simply don't have enough sperm to go round, so have to ration it out. It is not known how many other creatures follow this pattern of behaviour, but the human parallels are hard to ignore!