Some animals see sex as a sport, an athletic competition. For them, mating is a contest of sexual conquest where the male who “makes love” to the most females wins. It is about physical pleasure, not procreation, about sexual gratification, not gratitude. But some animals engage in mating rites that don’t involve touching their sexual partner at all. Among these species, oysters take the prize.
In a feat best described as amazing, oysters change their gender from male to female and back again. Performing a sexual magic trick, they turn themselves from Robert into Roberta repeatedly, as often as they choose.
Oysters live anchored to oyster beds together with millions of other oysters. And every one of them is busy releasing sperm and eggs into the sea. A single oyster can release as many as one hundred million eggs at one time. So ‘cluster clouds’ composed of trillions of oyster sperm and eggs float beneath the sea.
How do oysters do this? They set in motion a sequence of events where the males become females, get themselves pregnant and give birth to countless offspring.
Think of playing a game of catch with yourself. You heave a ball, then sprint thirty yards at full-speed to catch the same ball you’ve just thrown... and you pull off this impressive feat, catching the ball before it lands. This is how oysters play the game of ejaculation, fertilization and procreation.
At the age of sexual maturity, all oysters are males. As males, they release their sperm into the water. Then they change themselves into females and produce eggs, which they also release into the water. As the eggs rendezvous with the swimming sperm, the females wait until the eggs are fertilized. Then they turn themselves back into males, beginning the process all over again.
The timing of these sex-change tricks is remarkable. Within each oyster there is a biological clock. This clock, which is governed by the cycles of the moon, signals every oyster to change gender at exactly the same time. If the existence of oysters was not yet known and ocean divers were to discover them tomorrow, then the next day’s headlines around the globe would proclaim: ’Life From Another Planet Found Beneath The Sea.’
Over the centuries, researchers have documented ‘the magic of love’ among species in the animal kingdom, including homo sapiens. The oyster’s sexual magic trick most clearly illustrates the difference between ‘sex’ and ‘making love.’ The first can be performed alone, but the second requires a partner.