by Margaret Dedloff
Orcas, also called killer whales, are marine mammals and the largest species of dolphin. Orcas can weigh up to 22,000 pounds, grow as long as 32 feet, and are found in all of the world’s oceans. Orcas can be recognized by their distinctive black and white coloration.
Orcas have varied diets based on where they live and hunt. These diets are based on what food is available in the area and how they were taught to hunt. Orcas can eat squids, seals, other whales, and even sharks. They are the only known predators of great white sharks.
Orcas live in groups called pods. A pod contains around 15 whales, all related through a single female orca, who leads the pod. Older females are at the top of the pod hierarchy and use their experience to guide the pod to the best fishing spots. Pods communicate with eachother underwater through the use of noises such as clicks, and each pod has its own unique dialect. Pod dialects and behaviors are taught to young orcas by older orcas in the pod. In addition to passing along dialects and behaviors, older orcas in the pod also teach hunting skills. Orcas coordinate with their pod to hunt as a team. For example, members of a pod can work together to create a wave to knock prey off of floating ice.
Beyond the pod, there are clans, which are groups of pods that share similar dialects. Communities are made up of groups of clans that associate together by habitat and diet. Communities of orcas, also called ecotypes, can be identified by their diet, appearance, and behavior. In the North Pacific, there are three main ecotypes: resident, transient, and offshore. Resident orcas can be found in many areas ranging from California to Russia. Resident orcas reside in large pods and eat mainly fish. The most famous of these are the Southern resident orcas that reside in the coastal waterways of the Pacific Northwest and exclusively eat endangered Chinook salmon. Unfortunately, this clan is endangered because of human activities like boat traffic and low populations of its primary food source.
There are two different ways that these ecotypes can be identified by humans. The first is by their dorsal fin, the fin on the top of the orca. The shape and how the fin curves can give clues to what ecotype the orca belongs to. You can also identify these ecotypes by their saddle patches, which are the patch of white directly behind the dorsal fin (see image below).
Transient orcas, also called Bigg’s orcas, have straighter dorsal fins and reside in smaller pods. Bigg’s orcas get their names from Dr. Michael Bigg, the scientist who first realized that they behaved differently from resident orcas. They mainly eat seals, squid, sea lions, and porpoises. Like resident orcas, transient orcas can also be found in the Pacific Northwest.
Offshore orcas are found farther offshore than the other two ecotypes. They can be found as far as 9 miles away from the coast. Offshore orcas congregate in big groups and hunt fish, including sharks.
Orcas are important members of the ocean community, but their populations can be hurt by human activity. Our actions, no matter how far we are from killer whales, can aid in protecting these animals. To help decrease the threats facing orcas, we can reduce our use of plastics, eat ethically sourced fish and educate others! Reducing our use of plastics helps to keep the oceans cleaner and keeps harmful toxins out of the orcas’ food sources. It is important to eat ethically sourced fish so we can decrease overfishing of important species, like Chinook salmon, that are important food for orcas. The best way to raise awareness for orcas is to spread knowledge about them, so go tell your friends about the social life of orcas!
