A black rhinoceros calf was born to first-time parents, mother Kati Rain and father Ajabu (pronounced ah-JAH-boo), at the Saint Louis Zoo on January 14, 2011. The little maled weighed 120-1/2 pounds at birth, and was named Ruka. Ruka spends his days with his mother in River's Edge. They are most active and most easily seen during the morning hours.

This is the first black rhino calf to be born at the Saint Louis Zoo in 20 years. In all, eight black rhino calves have been born at the Zoo.

Kati Rain and Ajabu arrived at the Zoo's River's Edge in 2007. Kati Rain is from Sedgwick County Zoo, and Ajabu from San Diego Zoo Safari Park. 

At age 4, Ruka moved to the Oregon Zoo to pair with a compatible female at the recommendation of the SSP. Ruka's parents live at River's Edge.

The black rhino has experienced the most drastic decline of any rhino species. In 1970, it was thought there were about 65,000 black rhinos in Africa. By 1993, there were only 2,300 survivors in the wild. Black rhinos are heavily poached, because it is thought in many Asian countries that the rhino horn has medicinal uses.

The Saint Louis Zoo's black rhinos are part of the Association of Zoos and Aquariums' Black Rhino Species Survival Plan (SSP), a program to manage a genetically healthy population of black rhinos in North American zoos. Currently there are 60 black rhinos in 38 institutions.