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Destination: Galapagos Islands Cyber Field Trip

Wildlife of the Islands: Marine Life

By clicking on the linked words, you can also learn more about some of the scientific terms used frequently throughout this site.

Fur Seal
Arctocephalus galapagoensis
Fur seal photo courtesy of Michael Jackson. Copyright 1993.The Galapagos fur seal is little-known because it lives only on the Galapagos Islands. It is the smallest of all fur seal species, growing to only about five feet in length. It is light tan in color with grayish brown coloring on its back. Sealers nearly exterminated the Galapagos fur seal population permanently by slaughtering untold thousands in the 18th and 19th centuries. The population has recovered slightly since but has never reached its former numbers.

Hammerhead Shark
Sphyrna tiburo, Sphyrna lewini
The tiburo or bonnethead subspecies of hammerhead shark is the most prevalent of all shallow water sharks. This shark's eyes are located on the sides of its distinct, shovel-shaped head, and its nostrils are on the front corners of the "hammer." Found only in warmer waters, the bonnethead is about six feet in length and is gray or grayish brown in color. The lewini or scalloped subspecies of hammerhead has large indentations at the center and on either side of the front of its head. The scalloped hammerhead grows to about 10 feet in length and is light gray and white in color.

Marine Iguana
Marine Iguana; photograph by Martin WikelskiThe marine iguana is the only sea lizard in the world and can only be found in the Galapagos Islands. Scarcity of vegetation on the volcanic islands likely led some land iguanas to seek food along the shoreline and gradually underwater, leading to the development of the marine iguana. These vegetarian creatures swim as far as 50 feet below the surface of the water in search of seaweed, and can stay underwater for up to a half-hour. About four to five feet in length, they gather in large groups on the rocky island beaches to bask in the sun. Young marine iguanas are charcoal in color, but adult males may be red or brown. Members of the Hood Island subspecies sport bright patches of red and turquoise.

Sally Lightfoot Crab
Grapsus grapsus
Sally Lightfoot Crab; photograph by Silvia Siegel The Sally Lightfoot crab is a climbing crab that uses the spines on the ends of its legs to cling to rocks. Named by sailors in honor of a 19th century dancer, this crab is bright yellowish-orange in color and is found in great numbers throughout the Galapagos Islands. Sally Lightfoot crabs frequently crawl directly over the marine iguanas that bask on the lava rocks these two species share.

Sea Lion
Zalophus californianus wollebaeki
Sea Lion; photograph by Silvia SiegelThe sea lions that live around the Galapagos Islands are a subspecies of the common Californian sea lion and are found only in the Galapagos. These shore-living creatures feed mainly on squid, octopus and fish, and rarely venture more than 10 miles out to sea. They are approximately six feet in length and brown in color. Sea lions are highly intelligent and are often seen performing in water shows.

Now that you know about the marine life of the Galapagos Islands, find out more about the land-dwellers and birds.

Scientific American Frontiers would like to thank Michael Jackson, author of Galapagos - A Natural History, for the use of his photos.


Scientific American Frontiers
Fall 1990 to Spring 2000
Sponsored by GTE Corporation,
now a part of Verizon Communications Inc.