Abundance Estimation; Aerial Behavior; Age Estimation; Aggressive Behavior; Albinism; Amazon River Dolphin; Ambergris; Antarctic Fur Seal; Antarctic Marine Mammals; Archaeocetes, Archaic; Arctic Marine Mammals; Atlantic Spotted Dolphin; Atlantic White-sided Dolphin; Australian Sea Lion; Australian Snubfin Dolphin; Baculum; Baiji; Baikal Seal; Balance; Baleen; Baleen Whales (Mysticeti); Baleen Whales, Evolution; Barnacles; Basilosaurids and Kekenodontids; Beaked Whales, Overview; Bearded Seal; Behavior, Overview; Beluga Whale; Berardius Beaked Whales; Biogeography; Biotelemetry; Blubber; Blue Whale; Bones and Teeth, Histology of Bottlenose Dolphin, Tursiops aduncus, Indo-Pacific bottlenose dolphin; Bottlenose Dolphin, Tursiops truncatus. Common bottlenose dolphin; Bottlenose Whales; Bowhead Whale; Bow-riding; Brain; Breathing; Bryde's Whale; Burmeister's Porpoise; Bycatch; California, Galapagos and Japanese Sea Lions; Callosities; Cape and Australian Fur Seals; Captivity; Caspian Seal; Cephalorhynchus Dolphins; Cetacea, Evolution; Cetacean Ecology; Cetacean Life History; Cetartiodactyla; Circulatory System; Climate Change; Clymene Dolphin; Coloration; Common Dolphin; Communication; Conservation; Crabeater Seal; Culture and Social Learning; Cuvier's Beaked Whale; Dall's Porpoise; Delphinids, Overview; Dental Morphology; Desmostylia; Dialects; Diet; Distribution; Diving Behavior; Diving Physiology; Dolphins, Porpoises, and Monodontids, Evolution; Dugong; Dusky Dolphin; Eared Seals (Otariidae); Earless Seals (Phocidae); Echolocation; Ecology; Elephant Seals; Embryology; Endangered Species and Populations; Endocrine Systems; Energetics; Entanglement of Whales in Fishing Gear; Epimeletic Behavior; Ethics; Evolutionary Patterns; Extinctions, Specific; False Killer Whale; Feeding Morphology; Feeding Strategy and Tactics; Filter Feeding; Fin Whale; Finless Porpoise; Fisheries Interactions; Folklore and Legends; Forelimb Anatomy; Franciscana; Fraser's Dolphin; Gastrointestinal Tract; Genetics and Genomics; Genetics, Forensics; Genetics, Management; Geographic Variation; Gray Seal; Gray Whale; Group Behavior; Guadalupe, Galapagos, and Juan Fernandez Fur Seals; Habitat Pressure; Hair and Fur; Hindlimb Anatomy; Harbor Porpoise; Harbor Seal; Harp Seal; Health; Hearing; History of Marine Mammal Research; Hooded Seal; Hourglass Dolphin; Humpback Dolphins; Humpback Whale; Hunting; Hybridism; Identification Methods; Indo-Pacific Beaked Whale; Intelligence; International Whaling Commission; Inuit and Marine Mammals; Irrawaddy Dolphin; Killer Whale; Krill and other Plankton; Language Learning and Cognitive Skills; Leopard Seal; Locomotion, Terrestrial; Management and Conservation; Manatees; Marine Parks, Zoos, and Aquariums; Marine Protected Areas; Mark-Recapture; Mass Mortalities; Mating Systems; Melon-headed Whale; Mesoplodon Beaked Whales; Migration and Movement Patterns; Mimicry; Minke Whales; Molecular Ecology; Monk Seals; Musculature; Museums and Collections; Narwhal; Neoceti; New Zealand Fur Seal; New Zealand Sea Lion; Noise; Northern Fur Seal; Ocean Environments; Odobenocetops; Omura's Whale; Osmoregulation; Otters; Pacific White-sided Dolphin; Pantropical Spotted Dolphin; Parasites; Parental Behavior; Pathology; Peale's Dolphin; Pilot Whales; Pinniped Ecology; Pinnipedia, Evolution; Pinniped Life History; Pinniped Physiology; Pinnipeds; Playful Behavior; Polar Bear; Pollution; Popular Culture and Literature; Population Dynamics; Porpoises, Overview; Predation on Marine Mammals; Predator-Prey Relationships; Prey Consumption; Pygmy and Dwarf Sperm Whales; Pygmy Killer Whale; Pygmy Right Whale; Remoras; Reproductive Anatomy; Reproductive Behavior; Reproductive Physiology; Ribbon Seal; Right Whale Dolphins; Right Whales; Ringed Seal; Risso's Dolphin; River Dolphins; River Dolphins, Evolution; Ross Seal; Rough-toothed Dolphin; Scrimshaw; Sealing; Sei Whale; Sensory Biology; Sexual Dimorphism; Shepherd's Beaked Whale; Signature Whistles; Sirenian Life History; Sirenian Evolution; Skeleton; Skull; Sociobiology; Song; Sound; Sound Paths; South American Fur Seal; South American Sea Lion; Species & Subspecies; Spectacled Porpoise; Sperm and Beaked Whales, Evolution; Sperm Whale; Spinner Dolphin; Spotted Seal; Steller Sea Lion; Steller's Sea Cow; Stock Identity and Assessment; Strandings; Streamlining; Striped Dolphin; Subantarctic Fur Seal; Surveys; Sustainability; Susu and Bhulan; Swimming; Systematics; Territorial Behavior; Thermoregulation; Thorax and Abdomen, Anatomy; Tool Use; Toothed Whales (Odontoceti); Tourism; Training; Tucuxi and Guiana Dolphins; Tuna-Dolphin Issue; Vaquita; Vision; Walrus; Weddell Seal; Whale Lice; Whaling, Illegal and Pirate; Whaling, Japanese; Whaling, Modern; Whaling, Traditional; Whiskers; White-beaked Dolphin