Field Guide to Orcas
Also known as killer whales, orcas are renowned for their finely tuned hunting skills, but this is only part of the story, says Rob Lot, policy manager for the Whales and Dolphin Conservation Society (WDCS). Here is his guide to these complex ocean predators and what you need to consider before booking a trip to see them in the wild.
Orcas are iconic. Their historic reputation as ruthless killers has given way to a greater appreciation of an animal that scientists now believe may be second only to humans in terms of behavioural, linguistic and ecological diversity and complexity. Orca populations have unique dialects, are self aware and possess a rich culture which is passed down through the generations. They are incredibly powerful and capable yet at the same time exquisitely self-controlled. A striking feature of orca society is the virtual absence of overt aggression within and between pods, and there are no documented accounts of wild orcas deliberately attacking humans.Sadly, the one-dimensional caricature on display in the world's marine parks pays a great disservice to these powerful, sentient, apex predators that can be found across all the world's oceans. Our fascination with these universally recognisable animals, which are so like us in some ways yet so mysterious in others, has driven us to find out more about this charismatic species, the oceans they inhabit, the threats they face and, ultimately, how we can better protect them.
Although Orcinus orca, is currently considered to be a single worldwide species, recent research has revealed that there are at least 10 recognisable forms or ‘ecotypes’ of orcas. For the most part, the ecotypes have different prey preferences, distributions, social structures, foraging behaviours, physical features, genetics and make different sounds. These differences indicate that perhaps there are in fact several different species of orca. These intelligent, highly social animals live long lives in stable family groups or pods. Females on average live 50 years, but can reach a maximum of 90 years. Males average around 30 years, with a maximum of 60 years.
Orcas are the most widely distributed of the cetaceans (whales, dolphins and porpoises) in the world, and probably the most widely distributed mammal in the world after man. Clans of orcas roam every ocean of the world and most seas. They range from the polar ice edges to the tropics, and from the shoreline to the deep, open ocean. Generally though, they are more common in coastal waters with areas of high productivity in both temperate and polar regions.Any migration is usually in response to a change in prey availability and some animals have been shown to move long distances, for example, between California and Alaska – a distance of 2,000 km. Estimates vary, but the minimum global population of orcas is believed to be in the region of 50,000 whales – half of which are found in Antarctica.
Orcas are in fact the largest members of the dolphin family, with a robust, heavy body and a conical head. They have a striking colour pattern with a predominantly black body and a white belly. They have a conspicuous white patch above and behind the eye and a grey saddle patch behind the dorsal fin. Orcas in different geographical areas vary significantly in average size.Adult male orcas are unmistakable at sea, with an upright dorsal fin that reaches almost 2 metres in height. Males on average grow to 7-9.8 m in length and are 3.8-5.5 tons in weight. Females have a smaller, slightly curved dorsal fin, and grow 4.5-8.5m in length and are 2.5-4.5 tons in weight.
Orcas are highly versatile predators with a varied diet which is often determined by geographical location and population. In the Pacific Northwest, the ‘resident’ orca population (i.e. found in predictable locations at certain times of the year) primarily eat salmon, especially the large, fatty Chinook salmon, but will also take cod and herring. The ‘transient’ (or Biggs) orca population, which roam a much wider area, feed on other marine mammals such as seals, dolphins and porpoises. Orcas have even been known to attack the largest animal on the planet - the blue whale. There is a third orca population in this area, known as the ‘offshores’ which are seen in large groups and thought to feed on schooling fish.North Atlantic orcas feed on herring and mackerel, but will also take seals, whilst orcas in the Strait of Gibraltar show a preference for Bluefin tuna. In Antarctica, different orca populations prey on Weddell seals, minke whales, Patagonian toothfish and even penguins! In New Zealand waters, orcas typically hunt sting rays.
Watching orcas in the wild can be a hugely entertaining experience as they often exhibit a whole range of behaviour, from ‘spy hopping’ (poking their head out of the water to look around) to tail slaps and breaching, in which the orca gracefully leaps clear of the water. No one knows for sure quite why orcas breach. It may be a form of communication or a way to rid the skin of parasites, or maybe they just do it because they can! Orcas are also one of the fastest creatures in the ocean, capable of swimming at speeds of up to 55km/h (34mph).Orcas possess one of the largest brains on the planet, and so have developed some highly complex and sophisticated hunting strategies. Perhaps the most spectacular behaviour is that witnessed amongst orcas in Antarctica, where certain populations use a hunting technique known as ‘wave washing’. At the start of a hunt, orcas patrol the pack ice ‘spy hopping’ for Weddell seals hauled out on the ice floes. Once an orca has spotted some potential prey, it calls in more orcas, and together they then form a single line and swim quickly in unison towards the ice floe. Their powerful tail strokes generate a large wave which crashes over the floe and washes the hapless seal into the sea, where the orcas are waiting. Another hunting technique known as ‘carousel feeding’ has been perfected by orcas off the coast of Norway. This technique involves orcas cooperatively herding schools of herring into a tight ball and driving them towards the surface, then picking off individual fish that have been stunned by tailslapping.Along the wild, windswept coast of the Peninsula Valdes in Patagonia, a small group of orcas have developed a high-risk hunting strategy that involves ‘intentionally stranding’ themselves on the beaches to snatch sea lion and elephant seal pups from the surf zone. This unique hunting strategy is practiced by only some members of this community, with other members relying on the hunters to ‘food share’.
Orcas are long lived and slow to reproduce, and so invest a lot of care and time in raising their young. Typically, a female has her first calf at around 13 years of age after a 17-month gestation period. Females then have calves at approximately 3-5 year intervals up until their forties when, like humans, they enter menopause. Females can live for decades after the menopause and become a ‘grandmother’ or matriarchal figure within the pod, contributing to its success by sharing parenting knowledge and supporting the younger females. Research into the fish-eating orcas of the Pacific Northwest has shown that sons stay with their mothers their entire lives and that mating is likely to occur when the pod occasionally comes together with other groups to form what is known as a ‘Super Pod’.
Orcas are the oceans’ top predators and are considered a ‘sentinel species’ because their health is an overall indicator of the oceans’ ecological health. The major threats to the world’s orca population can broadly be divided into declining food availability, pollution, and physical and acoustic disturbance. Some populations are seriously threatened by overfishing and man’s manipulation of the environment, e.g., the damming of important salmon spawning rivers. Orcas sit at the top of the food chain and therefore accumulate high levels of toxins in their blubber. One contributing factor to infant mortality, which can be as high as 50% amongst firstborns, occurs when orca mothers offload their toxins to their young through their milk.Another threat comes in the form of increasingly busy and noisy oceans – hearing is the most important sense for orcas, so they find it increasingly difficult to navigate, communicate and feed in such conditions.One other major threat to this species arose from the public’s desire to see them on display in marine parks. In the 1960s and early 1970s, orcas from the Pacific Northwest were captured for display in marine parks across North America. Some of these populations have yet to recover from these captures and are today listed as ‘endangered’. More recently, wild orcas from Iceland and Japan were taken into captivity. Even today Russia issues permits for up to ten orcas to be taken from its waters each year (though to date only two have been taken which both died soon after capture.). Orcas are supremely adaptable marine mammals, but only time will tell if they can alter their lifestyle and prey preferences to keep pace with the accelerating manmade and environmental changes that threaten their habitat.
Where to see them in the wild
USA and Canada
Perhaps the world’s best and most famous location to see orcas are the waters off Washington State, British Columbia and Alaska. A population of orcas known as the Southern Residents numbering around 88 animals, can be seen from May to October around the San Juan Islands. Whale-watching boats operate out of Victoria, Friday Harbor, Anacortes and Vancouver. Whale watching is very popular here, so expect to be on the water with lots of other boats. If you are visiting San Juan Island, a trip to Lime Kiln State Whale Watch Park is highly recommended. This unforgettable land-based experience gives visitors a whole new perspective, as the orcas often come within metres of the shoreline.At the northern end of Vancouver Island lies Johnstone Strait, which is the core area for the Northern Resident orca population. Orcas tend to arrive in the area in early July, following the first salmon runs, and stay around until November. Whale-watching boats operate out of Telegraph Cove, Port McNeill, Alert Bay and Campbell River. Further south along the California coast, marine mammal-eating orcas can also be seen in Monterey Bay following the grey whale migration.
When to go: Head to Monterey Bay in April and May; Washington State and lower BC any time from May to October; Northern Vancouver Island from July to October and SE Alaska from April to November
A unique population of orcas has been identified around the Peninsula Valdes region of Patagonia. The orcas here have mastered the behaviour of intentionally stranding themselves on the beaches to grab sea lion pups off the beach. The population consists of about 18 animals, though not all of them strand – non-stranding orcas therefore rely on other members of the community to ‘food share’. The best times to see this behaviour are during March and April, when the naïve sea lion pups start to explore their world and congregate in the surf zone.
When to go: It is possible to see orcas in the Peninsula Valdes region of Patagonia throughout the year but particularly during March and April, when you can witness deliberate stranding behaviour from the lookout at Punta Norte around high tide.
While orcas can be seen year round off the coast of Iceland, in recent years large numbers of overwintering herring have brought pods of orcas into the fjords around the Snaefellsnes peninsula. January to April is the best time of year to observe this feeding behaviour, with most whale watching organised from the village of Grundarfjordur. Tours here form part of a long-standing North Atlantic research project on orcas and researchers have used photographs taken by passengers to identify individual animals. This allows the researchers to increase their knowledge of the Icelandic orca population and to see how their movements relate to prey availability. In the summer months, orcas are often seen along Iceland’s south coast around the Westman Islands. Orcas occasionally seen off the north coast of Scotland and the northern isles of Shetland and Orkney have been identified as being a part of the Icelandic herring-eating population.Iceland boasts some fantastic whale-watching opportunities where other species (humpback, fin and minke whales) can be seen in addition to orca from May to September. Trips are organized from several ports, including Reykjavik, Husavik, Keflavik and Hofn.
When to go: Orcas can be seen year round off the coast of Iceland, more recently in specific areas like the fjords around the Snaefellsnes peninsula. January to April is the best time of year to observe orcas feeding, with most tours embarking from Grundarfjordur.
Strait of Gibraltar, Spain
The presence of orcas in the Strait of Gibraltar is related to the seasonal migration of bluefin tuna. Two groups of orcas, totaling about 40 animals, feed on tuna during two different seasons and using two different hunting strategies. Orcas associated with the trap net fishery along the Spanish coast are mainly observed from April to June. A second group are often observed stealing tuna off the lines of Moroccan and Spanish fishermen along the Moroccan coast from July to September. Whale watching trips run out of Tarifa on the Costa de la Luz.
When to go: Orcas can be seen hunting the bluefin tuna in the Strait of Gibraltar between April and June and along the Moroccan coast from July to September.
The Antarctic continent and the surrounding Southern Ocean are considered the largest marine mammal feeding grounds on the planet today. It is thought that half of the world’s populations of orcas can be found here. There are three different forms present: Type A, B and C, while a fourth, Type D, is found around the sub-Antarctic islands. Most cruise ship expeditions to Antarctica visit the wildlife-rich Antarctic Peninsula region where there is a good chance of seeing orcas in search of minke whales and seals. Further along the continent, and less visited due to its remoteness, lies the pristine wilderness of the Ross Sea where the orcas here prey on toothfish. The Antarctic season is November to March, with most trips departing from Ushuaia in Argentina. Departures to the Ross Sea are from Hobart in Australia or Invercargill in New Zealand.
When to go: Cruise ship expeditions to Antarctica between November and March are the best option when visiting the Antarctic Peninsula region as there is a good chance of seeing orcas in search of minke whales and seals.
The herring migration has recently changed in northern Norway and sightings are not as predictable as they once were. However, orcas are still frequently seen throughout the year around the coast and, during the winter months, can be seen hunting in the fjords. At this time of year the days are short but the clear nights can be magical with the northern lights dancing across the sky. The spectacular winter scenery of the Norwegian fjords is a fitting backdrop to the orcas which can be seen round the Lofoten Islands, Andfjorden and Tysfjorden.
When to go:
Head to the Norwegian Fjords during the winter months to see the orcas at their most active. Whale watching trips operate out of Sto, Andenes and Tysfjord.
Watching orcas in the wild is a thrilling experience but our very presence on the water has an effect on the wildlife and their habitat. Orcas need space to find food, choose a mate, raise young, socialise and rest. If we get too close, move too fast or make too much noise, we may disrupt these activities and cause the animals stress and physical harm. Orcas should never be chased or harassed, and it is important to let them decide what happens.While in the presence of orcas, keep a respectful distance, maintain a slow, steady speed and always keep the path of the whales clear. Special care should be taken around mothers with young.There are some important considerations to think of when booking an organised whale watching tour. Ask the operator if they follow an approved ‘Code of Conduct’, and whether a trained naturalist and/or researcher will be onboard. This makes for a prime recreational and educational experience, and motivates passengers to care about the whales, the oceans and marine conservation.
About the Whale and Dolphin Conservation Society
Established back in 1987, the Whale and Dolphin Conservation Society (WDCS), is the leading global charity dedicated to the conservation and welfare of all whales and dolphins.We defend these remarkable creatures against the many threats they face through campaigns, field research, rescue work, advising governments and conservation projects. WDCS exisits to create a world where every whale and dolphin is safe and free. For more information go to www.whales.org