Topeka ? An 8-year-old Nile hippopotamus has given birth at the Topeka Zoo.

Visitors on a once-a-month “Twilight Tour” of the zoo watched the delivery Friday night.

The mother, Mara, had been on a contraceptive and was just found to be pregnant Thursday. She went through three hours of labor.

The sex of the approximately 60-pound baby has not been determined.

Zoo director Brendan Wiley says the baby appears to be in good health, but zookeepers don’t know for sure because they haven’t seen it nurse yet.