Although the sea offers a bounty of animal life to the people of the Northwest Coast, the rugged terrain of the coast and the rough waters make hunting a challenge. Faced with the challenges of making a life in this environment, the Tlingit people developed skills that enabled them to reap the harvest of their most accessible resource, the sea.

Seals and sea lions were the most valuable sea mammals to the people of the Northwest Pacific Coast. Symbols of wealth and plenty, they provided food, clothing, and medicines. In addition, skins were fashioned into floats and bags, the intestines into string and bow-strings, and the bladders into containers.

The Northern Pacific is home to a number of different species of sea mammal. The harbor seal (Phoca vitulina) lives everywhere along the coast and enters many rivers. The northern fur seal (Callorhinus ursinus) is an offshore migrant. The northern sea lion (Eumetopias jubatus) ranges along most of the coast, frequenting both offshore islands and estuaries. The smaller California sea lion (Zalophus californianus) and large northern elephant seal are found in the area as well.

Most Pacific Coast peoples admired whales from afar. Hunting these mammals required both great skill and endurance. The whale was never actively hunted by the Tlingit; however, beached whales were an important resource. A single whale could provide a village with blubber and skin for food, bone for tools, sinew for rope, and oil for lamps.

Before commercial whaling, the most common species of larger whales were the humpback whale (Megaptera novaeangliae), which often entered straits and sounds, and the gray whale (Eschrictius gibbosus), which migrates seasonally just off the outer coast.

The orca or killer whale (Orcinus orca), once commonly called blackfish, is present all along the coast and and abundant in waters from Alaska to Puget Sound. Killer whales were a clan symbol for many tribes.

The sea otter (Enhyda lutris) was once very common all along the outer coast. With the Europeans arrival in 1780, their pelts became the most sought-after trade product, resulting in the animal's near extinction.