A Family Affair
Kayleigh Brookes is a nature conservationist, writer, and campaigner living in the United Kingdom. She loves the ocean and all of its wonderful inhabitants, especially orcas. She is passionate about protecting the natural world, celebrating its wonders, raising awareness of issues, and tackling them.
There are about ninety species of whales and dolphins in our seas, with incredibly diverse behaviors, cultures, and social structures. Toothed whales are amongst the most intelligent creatures on earth. They communicate using a series of clicks, calls, whistles, and echolocation to navigate and hunt. As a general rule, most toothed whale species are incredibly social, although the degrees of sociality differ between species, and can even be different within species.
Unlike toothed whales, baleen whales are usually either alone or in small groups. While large groups of baleen whales are very uncommon and don’t echolocate, they do make vocalizations, and even when alone, in acoustic contact with one or more others.
Orcas, or killer whales, are the largest species of dolphin, all of which are classified as toothed whales. The social structure and culture of orcas are incredibly sophisticated and said to have no parallel apart from human societies. This, however, may simply be the fact that most dolphin species have not been studied in any depth. The orca pod is a matriarchal society, and all pods have strong matrilineal connections. This means that a female is the center of the killer whale world.
Bonds are extremely tight between pod members and last for a lifetime. Calves stay with or near their mothers throughout their lives, and while female offspring may break off to start their pods, these usually stay near their mother’s pod, and will often join up with other related pods, forming what is known as a clan. Males in the pod will often leave to mate with other orcas but then return to the family pod. Sometimes a single pod can contain four generations and can number up to 50 individuals.
Within these family groups, all adult whales take part in raising the calves. Other orcas within the pod will babysit youngsters, which is known as “alloparenting.” This altruistic behaviour helps take the pressure off the mother, strengthens the bond between the orcas, and allows for the passage of knowledge and culture from orca to orca and generation to generation.
Pod members of both sexes teach the youngsters essential skills such as hunting techniques, social interaction, knowledge of feeding and breeding grounds, and migration routes. Each pod has its distinct calls and vocalisations – dialects that are learned and passed down from one generation to the next. Clans all share similar vocalisations and calls, although some are exclusive to individual pods.
“Overt violence or aggressive behaviour between individuals, even among males, has never been observed. Instead, orca society is marked by cooperation, coordination, communication, trust, and acceptance.” - OrcaLab
Orcas work together to hunt, and they can eat a variety of food. However, different pods have different feeding preferences, and some may eat a variety of food whereas others specialise on one prey type. This could be because it is more readily available, or because these orcas have adapted to become adept at catching it.
For example, some orca pods feed solely on fish, and others specialise in other marine mammals, such as seals and dolphins. Some pods focus on sharks and rays. Interestingly, orcas that eat other mammals live in smaller pods and hunt silently, so as not to alert their prey to their presence. In comparison, fish-eating orcas live in much larger pods and communicate constantly as fish cannot hear their sounds.
The most studied orcas in the world are the resident orca pods off the west coast of Canada and the USA. These resident pods are so named because they stay in inland or nearby coastal waters to feed on salmon. There are two sub-groups of residents, the Northern Residents that range from Vancouver Island to Southeast Alaska, and Southern Residents that occupy greater Puget Sound. These two groups are separate from each other and tend not to overlap. Both populations are clans made up of several pods that are all related matrilines.
In comparison to the resident orcas, there is another population in the Pacific Northwest known as transients. Transient orcas range over wider areas and further out into the open sea. Their pods are still made up of matrilines; however, they tend to have fewer individuals. This could be because their prey consists entirely of marine mammals, who would be alerted by a large orca group. Transients and residents are distinct genetically and are not thought to interbreed. They also do not share any calls or vocalisations, as apparently unique populations.
The Icelandic Orca Project researches and monitors the orcas that are seen around Iceland to aid in their conservation and protection. They have found that the orcas do not always remain in the area all year and some regularly travel to the north of Scotland. Hence, it is possible to see orcas in the United Kingdom. Around Orkney and Shetland, there is a fairly large community of orcas, and it is thought they belong to a population that also ventures to Iceland and Norway.
Photo ID is being used as a tool to compare individuals seen in both Icelandic and Scottish waters, as well as in other areas of the world, such as the Pacific Northwest. This method identifies individual orcas by the shape and size of their dorsal fins and the color and pattern of the whitish saddle patch just behind the dorsal fin. By photographing individual orcas and comparing photos over time, one can get a sense of which orcas have calves, which orcas interact with others, and where they move.
There is a small pod in the Hebrides known as the West Coast Community, which is the only resident pod of orcas in the United Kingdom. Sadly this pod now only numbers eight individuals, four males and four females, and the population is under threat due to high levels of contaminants in the ocean. The Hebridean Whale and Dolphin Trust have been monitoring this population for almost twenty years and have established an extensive catalog of the orcas to ID the individual animals and track their movements.
Similar problems of toxic contaminants threaten the Southern Resident orcas of Puget Sound, along with a decline in their main prey, Chinook salmon, due to dams and stream degradation used by the salmon for spawning. The International Marine Mammal Project of Earth Island Institute has pushed for the removal of several key dams that would open up miles of salmon spawning streams in the Pacific Northwest for the salmon to feed the orcas.
Your donations are needed to help the International Marine Mammal Project’s conservation efforts on behalf of orcas and other whales and dolphins around the world. Your support would be very much appreciated. Thank you!
