Ocean
Master of open marine waters, balancing salinity through osmoregulation and traversing major planetary currents.
Mimic Octopus
The octopus that acts out toxic animals, and seems to pick the impression to suit the threat.
Moon Jellyfish
A see-through pulsing bell that ranks among the most energy-efficient swimmers on the planet.
Narwhal
Deep-diving Arctic whale whose spiral tusk can grow up to 9.8 feet and may double as a sensory tool.
Ocean Sunfish (Mola Mola)
Up to 1.3 tonnes of cartilage-and-jelly fish with no tail fin. It dives for siphonophores, then floats flat at the surface between dives.
Ocellaris Clownfish
A reef fish about 8 cm long that shelters among stinging anemone tentacles, where the breeding male turns female if the female is lost.
Orca (Killer Whale)
Matrilineal pod dialects, cooperative wave-washing tactics, and apex oceanic dominance.
Osprey
The fish-hawk that hovers over water, then plunges feet first to grab a fish in its talons.
Pacific Oyster
A stay-put oyster that starts life male, hears underwater sound and filters up to 50 gallons of seawater a day.
Polar Bear
Arctic apex predator with hollow, see-through fur over jet-black skin, a nose that smells seals 20 miles off, and a shrinking sea of ice to swim.
Portuguese Man o' War
Colonial siphonophore sail, up to thirty-meter neurotoxic tentacles, and ocean surface drifter.
Quokka
A Western Australian wallaby with three kinds of colour cone, a permanent grin, and no fear of tourists.
Red Abalone
A one-shell snail relative that clamps onto rock with a muscular foot and builds mother-of-pearl 3000-fold tougher than the mineral it is mostly made of.
Red King Crab
A spiny crab that can reach 24 pounds and a 5-foot leg span, and can only grow by shedding its shell.
Red Lionfish
Swims at half its prey's speed and still wins six lab chases in ten.
Red-Lipped Batfish
A Galápagos batfish whose genus walks the seabed on modified fins.
Saltwater Crocodile
Up to 23-foot apex archosaur, and the species behind the highest bite force measured in any animal: 3,689 pounds.
Sandfish Sea Cucumber
A sediment-swallowing sea cucumber that is one of the highest-valued species in the bêche-de-mer trade.
Scalloped Hammerhead
A wide head that seems to sense prey no better than a sandbar shark's, but searches a wider area and can pivot into sharp turns at high speed.
Scaly-foot Snail
The hydrothermal vent gastropod whose foot scales and shell are often mineralised with iron sulfide, with a heart that takes up about 4% of its body volume.
Sea Lamprey
A jawless survivor from a lineage that split from ours roughly 500 million years ago, armed with a sucker mouth ringed in rasping teeth.
Sea Otter
The densest fur of any mammal, a rock tucked under one arm, and a keystone predator that stops urchins from overgrazing kelp forests.
Shortfin Mako Shark
Considered the fastest shark in the world: burst speeds up to 70 km/h, warm swimming muscle, and hook-like, razor-edged teeth.
Sockeye Salmon
A silver sea-going fish that turns bright red and swims back to the freshwater system where it hatched.
Southern Elephant Seal
The largest living carnivoran, with a roaring nose and blood built for breath-holds of up to two hours.