You've done the hard work in finding a mate but now comes the tricky bit - making sure the sperm will reach the egg. Episode Two, Sperm Quest, reveals extraordinarily intimate details of what occurs during sexual intercourse.
In terms of trying to win the 'Sperm Quest' - males seem by far to exercise the most desperate strategies. Male marsupial mice literally copulate themselves to death; rightwhales ejaculate genuine 'bucket-loads' to flush out the competition; some males have huge testicles, others have huge individual sperm - 20 times the length of their own bodies. The prize for most dastardly ploy goes to the aptly named bed-bug which circumvents the female's reproductive tract altogether by simply injecting sperm anywhere in her body with a sabre-like penis. Some penguins have resorted to 'prostitution' while the majestic Wandering Albatross reveals that 'monogamy' is not all it's cracked-up to be. Do animals have orgasms? Does 'rape' exist in the animal kingdom? Are females naturally promiscuous?
