Science, Tech, Math › Animals & Nature 5 of the Many Types of Seals Share Flipboard Email Print Animals & Nature Marine Life Marine Life Profiles Marine Habitat Profiles Sharks Key Terms Amphibians Birds Habitat Profiles Mammals Reptiles Wildlife Conservation Insects Forestry Dinosaurs Evolution View More By Jennifer Kennedy Marine Science Expert M.S., Resource Administration and Management, University of New Hampshire B.S., Natural Resources, Cornell University Jennifer Kennedy, M.S., is an environmental educator specializing in marine life. She serves as the executive director of the Blue Ocean Society for Marine Conservation. our editorial process Jennifer Kennedy Updated February 03, 2019 There are 32 species, or types, of seals on the planet. The largest is the southern elephant seal, which can weigh more than 2 tons (4,000 pounds) and the smallest is the Galapagos fur seal, which weighs, in comparison, a mere 65 pounds. 01 of 05 Harbor Seal (Phoca Vitulina) Paul Souders/Digital Vision/Getty Images Harbor seals are also called common seals. There is a wide range of locations where they are found; they often hang out on rocky islands or sandy beaches in large numbers. These seals are about 5 feet to 6 feet long and have large eyes, a rounded head, and a brown or gray coat with light and dark speckles. Harbor seals are found in the Atlantic Ocean from Arctic Canada down to New York, although they are occasionally seen in the Carolinas. They are also in the Pacific Ocean from Alaska to Baja, California. These seals have stable, and even increasing populations in some areas. 02 of 05 Gray Seal (Halichoerus Grypus) Andreas Trepte/Wikimedia Commons/CC BY 2.5 The gray seal's mouthful of a scientific name (Halichoerus grypus) translates to “hook-nosed pig of the sea.” They have more of a rounded, roman nose and are a large seal that grows to 8 feet in length and weighs over 600 pounds. Their coat may be dark brown or gray in males and lighter grayish-tan in females, and it may have lighter spots or patches. Gray seal populations are healthy and even increasing, leading some fishermen to call for culling the population due to concerns that the seals eat too many fish and spread parasites. 03 of 05 Harp Seal (Phoeca Groenlandica/Pagophilus Groenlandicus) Tom Brakefield/Getty Images Harp seals are a conservation icon that we often see in the media. Images of fuzzy white harp seal pups are often used in campaigns to save seals (from hunting) and the ocean in general. These are cold-weather seals who live in the Arctic and North Atlantic oceans. Although they are white when born, adults have a distinctive silvery gray with a dark "harp" pattern on their back. These seals can grow to about 6.5 feet in length and 287 pounds in weight. Harp seals are ice seals. This means that they breed on pack ice in the winter and early spring, and then migrate to cold arctic and subarctic waters in the summer and autumn to feed. While their populations are healthy, there is controversy over seal hunts, particularly directed at seal hunts in Canada. 04 of 05 Hawaiian Monk Seal (Monachus Schauinslandi) National Marine Sanctuaries/Wikimedia Commons/Public domain Hawaiian monk seals live solely among the Hawaiian Islands; most of them live on or near islands, atolls, and reefs in the Northwestern Hawaiian Islands. More Hawaiian monk seals have been seen in the main Hawaiian Islands recently, though experts say that only about 1,100 Hawaiian monk seals remain. Hawaiian monk seals are born black but as grow lighter in tone as they age. Current threats to Hawaiian monk seals include human interactions such as disturbances from humans on beaches, entanglement in marine debris, low genetic diversity, disease, and male aggression toward females in breeding colonies where there are more males than females. 05 of 05 Mediterranean Monk Seal (Monachus monachus) T. Nakamura Volvox Inc./Photodisc/Getty Images Another type of popular seal is the Mediterranean monk seal. They are the world's most endangered seal species. Scientists estimate that less than 600 Mediterranean monk seals remain. This species was initially threatened by hunting, but now faces a host of threats including habitat disturbance, coastal development, marine pollution, and hunting by fishermen. The remaining Mediterranean monk seals primarily live in Greece, and after hundreds of years of hunting by humans, many have retreated to caves for protection. These seals are about 7 feet to 8 feet long. Adult males are black with a white belly patch, and females are gray or brown with a light underside.