His name is Mabu (which I think is short for something like Mabulahne, not sure of the spelling). He is a very large and robust male. Hard to see in the photo because of the lighting, but his left tusk has a metal cap to prevent a split from spreading further.
All calves are natural bred. This male calf - the larger of the two offspring in the photo - and his older brother (out of picture) were born at San Diego Safari Park. When this exhibit in Tucson opened a couple years ago, the herd was transferred here. The young female calf was conceived and born here in Tucson.