Mrithi, a 20-year-old male western lowland gorilla and the lead silverback of the zoo's gorilla troupe, wanders through the habitat at the Pittsburgh Zoo & PPG Aquarium on Wednesday, Feb. 13, 2013, in Pittsburgh. Officials at the zoo say Mrithi, mated with Moka, a 15-year-old female gorilla. A pregnancy test suggests that Moka is pregnant, though they must monitor the animal's behavior and weight to confirm the pregnancy. Moka's and Mrithi's first pregnancy resulted in a birth last year, but that baby male gorilla died after four months. (AP Photo/Keith Srakocic)