Panda Sex Tricks

Jonathan Watts describes some panda sex tricks in The Guardian:

Another challenge was the risk of in-breeding. To widen the genetic stock, researchers had to come up with a way to find a mate for even the least popular females. How did they do that? "We tricked them," Zhang says with a smile. The "trick" is to put a fertile and attractive female into a breeding pen, where she leaves scratchmarks and droppings capable of exciting a male. But at the last moment the females are swapped. The zookeepers introduce a new, less popular, mate who has been scented with the urine of the more attractive animals. She is introduced into the mating pen rear end first, so the male cannot see the face of his partner until after they have finished copulating. "When the males find out, they get very angry and start fighting the female," Zhang says. "We have had to use firecrackers and a water hose to separate them."