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Marine Animal Facts


The world of marine animals is a very diverse, fascinating group, and includes animals from relatively motionless invertebrates, to large whales and sharks who range across the oceans. View profiles of marine animals and answers to common questions.
  1. Cetaceans (Whales, Dolphins and Porpoises)
  2. Pinnipeds (Seals, Sea Lions, Walruses)
  3. Sirenians (Manatees, Dugongs and Sea Cows)
  1. Reptiles (Sea Turtles)
  2. Fish
  3. Invertebrates

Cetaceans (Whales, Dolphins and Porpoises)

A blue whale spouting

Cetaceans are mammals who are adapted to life in the water. There are over 80 species of whales, dolphins and porpoises on Earth, from the small Hector's dolphin to the huge blue whale. Below is information on cetaceans in general, profiles of whale species and answers to common questions about cetaceans.

Pinnipeds (Seals, Sea Lions, Walruses)

California Sea Lion (Zalophus californianus) Picture

The pinnipeds are mammals in the order Carnivora and suborder Pinnipedia. There are three families of pinnipeds: the Phocidae, the earless or ‘true’ seals; the Otariidae, the eared seals, and the Odobenidae, the walrus. These three families contain 33 species. Here are profiles of pinniped species and answers to questions about pinnipeds.

Sirenians (Manatees, Dugongs and Sea Cows)

Florida Manatee / USFWS

The Order Sirenia includes manatees, dugongs and the extinct Steller's sea cow. The sirenians are collectively also known as "sea cows," probably because they graze on sea grasses and other aquatic plants. Sirenians were named for the sirens of Greek mythology, who lured sailors with their song. Some think sightings of sirenians led to myths about mermaids.

Reptiles (Sea Turtles)

Loggerhead Sea Turtle (Caretta caretta), Juan Cuetos/Oceana-www.oceana.org

Sea turtles are reptiles that live in a marine or brackish environment. The flippers of sea turtles are long and paddle-like, making them excellent for swimming but poor for walking on land. Learn about sea turtles and the 7 species of sea turtles.


Bluefin tuna (Thunnus thynnus), photo courtesy NOAA

There are over 14,000 species of marine fishes, from the tiny pygmy goby to the giant whale shark. This group of vertebrate animals includes the jawless fishes, cartilaginous fishes (sharks, rays and chimaeras), and the bony fishes. Learn about some of these species here.


Northern Sea Stars and Green Sea Urchins / Blue Ocean Society

Invertebrates, animals without a notochord or backbone, comprise the largest group of organisms in the world, forming over a million species. Marine invertebrates alone comprise thousands of species, and are a hugely diverse group of animals, from sessile sponges to spiny sea urchins. Below are profiles and facts on some marine invertebrates.

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