An orca (sometimes called the wolf of the sea, killer whale or black fish) is a black and white carnivorous marine animal that lives near and in the Melting Sea.
- Orcas are members of the whale family, and are the biggest type of dolphin. They travel in groups called pods, and are sometimes known as "Wolves of the Sea" because of their ferocious appetite.
- Other than humans, sharks and polar bears, they are the top predator of the ocean, and they will even eat land animals such as caribou or moose if they are swimming in the ocean. They are very intelligent animals like dolphins are.
- They mainly feed on seals and sea lions, other whales, walruses, fish (including sharks, skates and rays), seabirds, squid, and octopuses, and even moose or caribou that are swimming to islands. Sometimes when starving, they will kill and eat polar bears and leopard seals, which are their biggest enemies other than humans. Other prey include sea otters and turtles. Orcas often prey on dolphins and porpoises (which are related) and cannibalize orca calves and dead adults. 
- Female orcas are called 'sows', males are called 'bulls' and young are called 'calves', like cows. Like dolphins and porpoises, they are social and live in pods, hunting and feeding together.
- Orcas killed Kallik's mother, Nisa, as well as one of Siqiniq's cubs, though she said it was very long ago. They guard their calves closely. Predators of the calves are polar bears, sharks, and leopard seals, though because of their weight, most of these animals scavenge their corpses rather than hunting the whales.
- Orcas can be found in all oceans, apart from the very top of the Arctic Circle. 
In The Original Series arc
- While traveling across the melting ice back to the mainland, Nisa, Kallik and Taqqiq encountered a group of orcas. When Nisa was helping Kallik swim to an ice floe, she was pulled under the water by the orcas and was killed.
- Kallik, Toklo, Lusa, and Ujurak come to an ice flow in the ice. Just before they jump in, orcas appear. They jump from ice block to ice block. Just before they get across, Kallik falls in. Suddenly, a pale white bear appears and scares the orcas off. This tells Ujurak that they are meant to be together.
- When traveling from the ice to the island, the bears encounter orcas. Kallik is immediately scared, remembering her mother's death. They need to swim across; and when the orcas almost kill Toklo, Ujurak shape shifts into one to fight them off.
In the Return to the Wild arc
- When the travelers come to a break in the ice, Kallik fears orcas were in the water. Orcas appeared to have scared away the seals and fish.
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