Apollo and Bella

A few weeks later, Apollo arrived at the zoo. He was a fine-built young male, but had a somewhat delicate air about him. His first meeting with Bella was calm. The two animals observed each other and gradually grew closer. Jessica, a young keeper, kept careful daily records. Over the course of several months, Bella and Apollo became good friends. Mike kept a daily record of how the two animals were doing. Eventually, it was time for mating. But the first pregnancy was a failure. What was the cause?

