Dominant rams can have too much of a good thing.
The biggest, butchest sheep throw their weight around, but they don't always live up to their image, a study of feral sheep has found. By the end of the rutting season, dominant rams are so drained by their sexual exertions that their sperm production tails off, and they lose out in the fatherhood stakes to fresher males lower down the pecking order. It's a ram's world on St Kilda. Human farmers abandoned this group of small islands 160 kilometres off the coast of Scotland in 1930. Emancipated from their two-legged oppressors, the sheep have given free reign to free love.