Two orang-utan babies recently born at a German zoo have held their first photo shoot on Friday (February 16). Orang-utan mother Annette gave birth to her fifth child on January 25, followed by a second baby which was born February 1 to first-time orang mother Miri. Orang-utans, together with the African gorilla, count among the most endangered great apes, according to Duisburg zoo. Keeper Frank Chomik, who has seen many apes give birth, was still concerned -- and impressed -- about the latest additions to his "family." The births, he said, "did not really come as a surprise." "But it came as a surprise to us how Miri behind is raising her baby so perfectly as a first-time mother." "During the first two or three days we are always extremely concerned about the babies, especially from first-time mothers," Chomik said. Although more than 50 orang-utans have been born at Duisburg zoo since 1962, offspring are still seen as something very special, especially when two healthy babies are born within a week of each other. Chomik and his team are happy that the mothers of both new babies immediately accepted their children. For now, "the orangs here are undergoing a visual preliminary check-up," Chomik said. "However, we can't just remove the baby from its mother because she would defend it with her life -- rightly so." "But we can still see that both babies are healthy. We installed a lot of protective measures like the glass windows to avoid children's diseases." "They could catch all sorts of diseases, including influenza. Once the time has come the mother will take the baby to the edge of the cage so that the veterinarian can carry out a check-up through the fence. We call this "medical training," Chomik said.