A male black rhinoceros was born at the St. Louis Zoo on May 17, the second in 26 years at the zoo. The boy was named Moyo, which means “heart” in Swahili, and he is bonding with his mother, Kati Rain, behind the scene.Another male calf, named Ruka, was born to the same parents in 2011 and later moved to the Oregon Zoo in 2015 to pair with a female there as part of the Association of Zoos and Aquariums Black Rhino Species Survival Plan.The endangered black rhino has experienced the most drastic decline of any of the five surviving rhino species, according to the zoo. Between 1970 and 1992, the black rhino population in Africa dropped by 96 percent. By 1993, only 2,300 black rhinos survived in the wild.