Urinary Estradiol in Captive Bonobos: Variation With Reproductive State and Sexual Swelling.

Summary: Scientists wanted to know if they could track the health and baby-making cycles of captive bonobos (a type of ape) just by testing their pee. They checked frozen pee from four female bonobos over four years. They found that a hormone called estradiol was much higher when the apes were pregnant. Also, the size of their physical swelling matched their hormone levels perfectly. This means zookeepers can use simple pee tests and just look at the apes to easily keep track of their health and pregnancy!