Changes

Killer whales have a distinctive color pattern, with black dorsal and white ventral portions. They also have a conspicuous white patch above and behind the eye and a highly variable gray or white saddle behind the dorsal fin.

Killer whales have a distinctive color pattern, with black dorsal and white ventral portions. They also have a conspicuous white patch above and behind the eye and a highly variable gray or white saddle behind the dorsal fin.

The species shows considerable size "dimorphism". Male adult killer whales can reach up to 32 feet (9.8 m) in length and can weigh nearly 22,000 pounds (10,000 kg); females can reach 28 feet (8.5 m) in length and can weigh up to 16,500 pounds (7,500 kg).  From a distance, males are further identified by their tall, straight-backed dorsal fins; females have smaller and hook-shaped dorsals.

The species shows considerable size "dimorphism". Male adult killer whales can reach up to 32 feet (9.8 m) in length and can weigh nearly 22,000 pounds (10,000 kg); females can reach 28 feet (8.5 m) in length and can weigh up to 16,500 pounds (7,500 kg).  From a distance, males are further identified by their tall, straight-backed dorsal fins; females have smaller and hook-shaped dorsals.

Sexual maturity of female killer whales is achieved when the whales reach lengths of approximately 15-18 feet (4.6 m-5.4 m), depending on geographic region. The gestation period for killer whales varies from 15-18 months, and birth may take place in any month. Calves are nursed for at least 1 year, and may be weaned between 1 and 2 years of age. The birth rate for killer whales is not well understood, but is estimated as every 5 years for an average period of 25 years.

Sexual maturity of female killer whales is achieved when the whales reach lengths of approximately 15–18 feet (4.6 m-5.4 m), depending on geographic region. The gestation period for killer whales varies from 15–18 months, and birth may take place in any month. Calves are nursed for at least 1 year, and may be weaned between 1 and 2 years of age. The birth rate for killer whales is not well understood, but is estimated as every 5 years for an average period of 25 years.

Life expectancy for wild female killer whales is approximately 50 years, with maximum longevity estimated at 80-90 years. Male killer whales typically live for about 30 years, with maximum longevity estimated at 50-60 years.

Life expectancy for wild female killer whales is approximately 50 years, with maximum longevity estimated at 80–90 years. Male killer whales typically live for about 30 years, with maximum longevity estimated at 50–60 years.

===Feeding===

===Feeding===

The diet of killer whales is often geographic or population specific. In the eastern North Pacific, the "resident" killer whale populations mainly feed on [[salmonid]]s such as Chinook and chum [[salmon]], while the "transient" population feeds on other marine mammals, such as Dall's [[porpoise]]s, Pacific white-sided [[dolphin]]s, California and Steller [[sea lion]]s, harbor [[seal]]s, sea [[otter]]s, and even large [[baleen whale]]s. Off the coast of Norway, killer whales mainly feed on [[herring]] and other schooling fish, often in a coordinated manner. In waters off New Zealand, killer whales feed on stingrays and sharks. Finally, in Antarctic waters, some killer whales hunt marine mammals and penguins, while others (presumably belonging to a different population) are observed feeding on Antarctic toothfish (Dissostichus mawsoni) and other fish species.

The diet of killer whales is often geographic or population specific. In the eastern North Pacific, the "resident" killer whale populations mainly feed on [[salmonid]]s such as Chinook and chum [[salmon]], while the "transient" population feeds on other marine mammals, such as Dall's [[porpoise]]s, Pacific white-sided [[dolphin]]s, California and [[Steller sea lion]]s, [[harbor seal]]s, sea [[otter]]s, and even large [[baleen whale]]s. Off the coast of Norway, killer whales mainly feed on [[herring]] and other schooling fish, often in a coordinated manner. In waters off New Zealand, killer whales feed on stingrays and sharks. Finally, in Antarctic waters, some killer whales hunt marine mammals and penguins, while others (presumably belonging to a different population) are observed feeding on Antarctic toothfish (Dissostichus mawsoni) and other fish species.

===Social habits===  

===Social habits===  

==Distribution==

==Distribution==

Killer whales are the most widely distributed marine mammals. They are found in all parts of the ocean and in most seas from the Arctic to the Antarctic. In the North Pacific Ocean, killer whales are often sighted from the eastern Bering Sea to the Aleutian Islands; in the waters of southeastern Alaska and the intercoastal waterways of British Columbia and Washington State; along the coasts of Washington, Oregon, and California; along the Russian coast in the Bering Sea and the Sea of Okhotsk; and on the eastern side of Sakhalin and the Kuril Islands, and the Sea of Japan. In the North Atlantic Ocean, sightings of killer whales are commonly documented up to the pack ice edge in Norwegian waters and around Iceland. In the South Atlantic and Pacific Oceans, killer whales are frequently sighted along the pack ice of Antarctica, and off the coasts of Patagonia, southern Argentina, and New Zealand.

Killer whales are the most widely distributed marine mammals. They are found in all parts of the ocean and in most seas from the Arctic to the Antarctic. In the North Pacific Ocean, killer whales are often sighted from the eastern [[Bering Sea]] to the Aleutian Islands; in the waters of southeastern Alaska and the intercoastal waterways of British Columbia and Washington State; along the coasts of Washington, Oregon, and California; along the Russian coast in the Bering Sea and the Sea of Okhotsk; and on the eastern side of Sakhalin and the Kuril Islands, and the Sea of Japan. In the North Atlantic Ocean, sightings of killer whales are commonly documented up to the pack ice edge in Norwegian waters and around Iceland. In the South Atlantic and Pacific Oceans, killer whales are frequently sighted along the pack ice of Antarctica, and off the coasts of Patagonia, southern Argentina, and New Zealand.

==Population Trends==

==Population Trends==