Skulls of New Species (IMAGE) NOAA Fisheries West Coast Region Caption The neotype skulls for Bigg's killer whale, Orcinus rectipinnus (left), and the resident killer whale, Orcinus ater (right). The Bigg's killer whale skull is more robust and has a wider rostrum (beak), which are presumably adaptations for feeding on larger prey such as marine mammals. Credit NOAA Fisheries/Southwest Fisheries Science Center Usage Restrictions No restrictions. License Public Domain Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.