Cetacea and two (external) limbs that are modified into flippers. Though not as flexible or agile as seals, cetaceans can swim very quickly, with the killer whale able to travel at in short bursts and the fin whale able to cruise at . Dolphins are able to make very tight turns while swimming at high speeds. The hindlimbs of cetaceans are internal, and are thought to be vestigial. Baleen whales have short hairs on their mouth, unlike the toothed whales. Cetaceans have well-developed senses—their eyesight and hearing are adapted for both air and water, and baleen whales have a tactile system
Strap-toothed whale individual was seen breaching between the South Orkney Islands and South Georgia. Strap-toothed whales' diet consists primarily of squid, although research has suggested that a small portion of their diet may also consist of fish or crustaceans. Adult males have a gape half the size of females and juveniles, limiting their squid to those weighing and less. Nothing is known about social organization of this species. This species has never been hunted or entangled in fishing gear. It is believed to be in a rather safe position compared with other mesoplodonts. Layard's beaked whale is included in the Memorandum of