A fully aquatic cetacean-esque creature evolved from Procellariiformes like the albatross/shearwater/petrel. Much like their airborne relatives, they propel themselves through the water with a pair of long pectoral flippers, using their fused pair of hind legs as a rudder. Most species feed on small fish, engulfing entire shoals into their gaping mouths. However, a few belonging to the Xiphos genus use their sharp, segmented beaks to subdue or shear chunks of flesh from larger animals. The tube-shaped nostrils characteristic of Procellariiformes have evolved to be situated closer to the top of the head, making it easier for the animals to breathe at the water's surface. Due to their inability to lay their eggs on dry land, Procellacetacea have become ovoviviparous.
