Washington designated the orca whale (Orcinus orca) as the official marine mammal in 2005 due to the research and persuasion of second graders from the Crescent Harbor Elementary School in Oak Harbor, Washington. This symbol is intended to promote orca awareness and to encourage protection of the natural marine habitat.

Pods of orcas migrate annually through Puget Sound and many people visit Washington state to watch them. The orca whale is a significant symbol for the Native American culture.

Orcas are a toothed black and white whales (also called killer whales and "wolves of the sea") and hunt everything from fish to walruses, seals, sea lions, penguins, squid, sea turtles, sharks, and even other kinds of whales. An orca whale may eat about 500 pounds of food a day.

The largest of all dolphins, male orcas average 19 to 22 feet in length (females average 16 to 19 feet.) Male orcas average 8,000 to 12,000 pounds in weight, females weigh 3,000 to 8,000 pounds. They are able to reach speeds up to 30 miles an hour and have good eyesight both underwater and above the surface. Orca whales live and hunt in cooperative pods, or family groups. Orcas work together with many hunting techniques.

Female orcas tend to live longer than males (females can live to be 90 years old, while males live about 50 years). Orca females average one birth every ten years to an eight-foot long, 400 pound calf (some may give birth every three to five years). An orca's only enemy is human beings.

Source:

State Symbols of Washington: Washington State Legislature
Creature Feature - Orcas: National Geographic Kids

Links:

State Animals - Mammals: 50 States List