The orca (Orcinus orca), also known as the killer whale or Galapagos killer whale, also less commonly known as ‘Blackfish’ or ‘Seawolf’, is a member of the infraorder Cetacea and is the largest member of the dolphin family (Delphinidae). It has a black and white patterned body and has been made famous by films such as Free Willy and Blackfish. These animals can be found all over the world and are only absent from the Baltic and Black seas, and some areas of the Arctic Ocean.
Orcas are a popular animal and attraction at marine theme parks, and, while wild orcas have never been known to attack humans, there have been incidents of captive orcas attacking and killing trainers at these parks. This has lead to a worldwide discussion on the ethics of keeping these large animals in captivity, particularly for entertainment purposes instead of conservation purposes.
Orcas are fascinating creatures, but unfortunately there is worry about their conservation status. Let’s explore more about the orca below and see what there is to learn.
An Introduction To The Orca Killer Whale
The Orca killer whale is found in all the worlds oceans, from the very cold Arctic and Antarctic regions to warm, tropical seas to the tropical cold seas of the Galapagos Islands.
Orcas come to the Galapagos archipelago in hunting rides and often you will find them near by places where there are sea lions. Orcas have been seen hunting dolphins and even Bryde’s whales. Orcas travel in familiar groups or pods, where a dominant male is the leader of the pod, accompany by two to four females and a young Orca or two.
Orcas are versatile and opportunistic predators. Some populations feed mainly on fish, others hunt marine mammals, including sea lions, seals and even large whales. There are up to five distinct Orca types, some of which may be separate subspecies or even species.
Orcas are highly social. Some populations are composed of matrilineal family groups (a system in which one belongs to ones mother’s lineage) which are the most stable of any animal species. The sophisticated social behaviour, hunting techniques and vocal behaviour of Orcas have been described as manifestations of culture.
The orca is one of 35 species in the oceanic dolphin family, which first appeared about 11 million years ago. The genus name Orcinus means “of the kingdom of the dead”, or “belonging to Orcus”, but the term “killer whale” is also used just as much as “orca”. Because the orca is part of the family Delphinidae, it is more closely related to other oceanic dolphins than to other whales.
Characteristics Of The Galapagos Killer Whale
There are three to five types, or ecotypes, of killer whales, and they may be distinct enough to be considered different races or subspecies. The three types that are currently identified are the resident orca, the transient or Bigg’s orca, and the offshore orca.
The resident orca is the most commonly sighted orca and is found in the coastal waters of the northeast Pacific. They normally visit the same areas constantly. The transient killer whale roams widely along the coast, having been sighted in both southern Alaska and California. They are usually seen in small groups of between two to six orcas. Transient and resident orcas live in the same area, but avoid each other.
Offshore orcas travel far from the shore, hence their name, and are normally seen in groups of 20–75. They are mostly seen off the west coast of Vancouver Island and near Haida Gwaii.
There have also been three, possibly four, types of orcas documented in the Antarctic, which differ in size, shape and pattern. They also have different diets and feed on different prey.
Male killer whales are called bulls, female killer whales are called cows, and baby killer whales are called calves.
Killer whales are very large with males ranging from 6 to 8 metres (20 to 26 ft) long and weighing more than 6 tonnes. Females are smaller, around 5 to 7 m (16 to 23 ft) long and weigh about 3 to 4 tonnes. Orca calves are around 180 kg (400 lb) and are about 2.4 m (7.9 ft) long at birth.
Being the most distinctively pigmented cetacean, you can’t mistake these animals! The orcas has a striking black and white body, with a mostly black back (dorsal) and white underside. They are also white around their jaw, but the white narrows between the flippers. Males and females have different patterns of black and white skin in their genital areas, and young orcas can look yellowish in color. As calves, they are born with a yellowish or orange tint, which fades to white.
They have very large rounded pectoral fins which resemble paddles and males have larger fins than females. Both males and females also have dorsal fins, although the male’s is about 1.8 m (5.9 ft) high and twice the size of the female’s. The male’s is also taller and more elongated than the female’s, which is shorter and more curved.
Killer whales have very strong jaws and sharp teeth, with the upper teeth falling into the gaps between the lower teeth when the mouth is closed. The back and middle teeth help to hold the orca’s prey in place. Their snout is also blunt and rounded.
Orcas have a white patch just behind their eyes and a grey or white “saddle patch” exists behind the dorsal fin and across the back. They have good eyesight both above and below the water, and very good hearing. They use echolocation to detect the location and characteristics of their prey.
They also have a good sense of touch and a layer of insulating blubber ranging from 7.6 to 10 cm (3.0 to 3.9 in) thick beneath the skin to help keep them warm.
The lifespan of wild female orcas is between 50 to 80 years old, while wild males tend to live shorter. The average age a male will live to is 29, although the maximum could be up to 60 years. It is thought that orcas that live in capacity generally live a shorter life, but this is up for scientific debate.
Female orcas are among the few animals that undergo menopause and live for decades after they have finished breeding.
Killer whales are carnivores, but exactly what they eat is determined by where they reside and what type of orca they are. Resident killer whales off the coast of British Columbia have a food source of fish, predominantly salmon, while transient whales in the same area will eat marine mammals and squid.
Orcas also munch on cephalopods, seabirds and sea turtles, and have been known to eat dolphins, young humpback whales, blue whales, sperm whales, dugongs, seals and Australian sea lions. They eat around 30 different species of fish, which can include sharks and rays, too.
Orcas have no natural predators and often hunt in groups like wolf packs. They spend most of their time in shallow waters, but will dive deeper if they are chasing prey. When hunting a large mammal such as a blue whale, as many as 50 killer whales will join the hunt to successfully kill the large whale. Orcas will also prey on the calves of whales and will concentrate on the weak or young.
A killer whale eats around 227 kilograms (500 lb) each day, on average. They either feed using a method called carousel feeding when catching fish, or disable larger prey like mammals by drowning them or slapping, ramming or landing on them to avoid injury and a fight. They are also known to chase whales to exhaustion before feeding on them.
Killer whales are very social animals, and live in social groups called pods. Pods usually consist of between a few and up to 20 orcas, but they can be much bigger, too, particularly if they are mating or trying to catch prey.
Unlike any other known mammal social structure, resident orcas live with their mothers for their entire lives. Often, there are special mods called matrilines that are made up of a the eldest female (matriarch) and her sons and daughters, and the descendants of her daughters, which can mean that as many as four generations travel and live together. Closely related matrilines will then form a larger pod together. Transient pods are smaller than resident pods, typically consisting of an adult female and one or two of her offspring.
Day To Day Life
The average day to day life of an orca consists of foraging, travelling, resting and socializing. Orcas frequently engage in spy hopping, breaching (jumping completely out of the water) and tail-slapping, which could be down to mating, communicating or simply just playing. Spy hopping behavior consist of the orca holding itself vertically in the water and kicking with its tail fluke in order to hold its head above the water line.
These animals also swim alongside porpoises and dolphins and can travel up to 40 miles a day on average.
Because orcas are social animals, they communicate a lot. They rely on underwater sounds to understand where each other are, for navigation and also to locate food. Members of the same pod communicate with each other through clicks, whistles, and pulsed calls, and each pod has a unique set of calls that are learned and culturally transmitted among individuals. These are known as dialects.
Females reach sexual maturity at about ten years old. They then have periods of polyestrous cycling (recurring physiologic changes that are induced by reproductive hormones) with non-cycling periods of between three and sixteen months. They reach peak fertility around 20, while males reach maturity at around 15, but do not typically reproduce until age 21. Female orcas can breed until the age of 40, after which they experience a rapid decrease in fertility.
The gestation period of an orca varies between 15 to 18 months. Male orcas mate with females from other pods, which prevents inbreeding, and females usually produce one calve in a single pregnancy, about every five years. There is no distinct calving season, so birth can take place in any month.
Unfortunately, mortality is extremely high during the first seven months of an orca’s life, when 37–50% of all calves die. Orca killer whale Calves nurse exclusively for at least a year, but remain in close association with their mother for the first two years.
Females give birth to an average of 5 calves over a period of 25 years, and then, when they no longer have calves, they play an important role in the family group – “babysitting” the calves of other females. Calves nurse for up to two years, but will start to take solid food at about twelve months. All resident Orca pod members, including males of all ages, participate in the care of young whales.
Typically, females live to the age of fifty, but may survive well into their eighties or nineties in exceptional cases. Males live to about 45 on average and up to 90 in exceptional cases. The lifespans of captive Orcas are significantly shorter, usually less than 25 years.
Migration patterns in orcas are poorly understood, but they are known to make seasonal movements.
Galapagos killer whales are considered to be very intelligent animals and have the second-heaviest brains among marine mammals. In captivity they can be trained and know how to teach skills to their young. They are also known to imitate others.
Orcas’ relationship with humans is a topic that has been discussed in great detail, particularly when it comes to captive orcas. Despite their name, in the wild, there are very few confirmed attacks on humans, and any that have occurred have not resulted in fatalities. There have been reports of wild orcas attacking boats, but it is thought that the behaviour is playful, rather than aggressive.
However, in captivity, orca attacks have been the cause of fatalities, particularly in orca trainers. The whales’ enormous size, color and ability train has made them a popular attraction at aquaria and aquatic theme parks, with many orcas being taken from the wild. Orcas are also bred in captivity and, by 1999, about 40% of the 48 animals on display in the world were captive-born.
While it often appears that orcas have a good relationship with trainers in captivity, critics say that the intelligence and large size of the animals means they do not suit life in captivity. Captive orcas also occasionally act aggressively towards themselves, their tankmates, or humans, which critics say is a result of stress. This has been shown in the critically acclaimed 2013 film Blackfish, which focused on the bull orca Tilikum who lived at SeaWorld Orlando until his death in 2017. The public’s growing appreciation of orcas has led to growing opposition to whale–keeping in aquariums.
Orcas are found in all oceans and most seas. They are mostly found in colder regions, such as Antarctica, Norway, and Alaska, where their large prey species are more abundant, but can also be found in temperate and tropical areas as well. Killer whales are most studied in the eastern North Pacific Ocean.
Of the three main types of killer whales, offshore orcas have the largest range, but are often found in the same areas as transient and resident orcas. Transient orcas are found most often in the waters surrounding Alaska’s Aleutian Islands and down to Southern California, and also along the coast of eastern Russia. Resident orcas inhabit the inland waters of Washington and British Columbia.
The world population of orcas is uncertain, but experts estimate that there are roughly 25,000 in the Antarctic, 8,500 in the tropical Pacific, 2,250–2,700 off the cooler northeast Pacific and 500–1,500 off Norway.
In 2008, the IUCN (International Union for Conservation of Nature) changed its assessment of the killer whale’s conservation status from conservation dependent to data deficient, recognizing that one or more killer whale types may actually be a separate, endangered species. In recent decades, several populations of killer whales have declined and some have become endangered.
There are two distinct populations specifically protected under federal law: the southern resident population that ranges from central California to southeast Asia (considered endangered by the Endangered Species Act), and the AT1 Transient subgroup in the eastern North Pacific. According to the National Oceanic and Atmospheric Administration (NOAA), the AT1 transient population has been reduced to just seven orcas, while the southern resident population is about 76.
Based on surveys conducted in 2006, the worldwide killer whale population is about 50,000 individuals left in the wild.
Predators Of The Orca
Killer whales are apex predators (predators that, as adults, are not normally preyed upon in the wild) at the top of the food chain and, while there are no natural predators of killer whales, whales are susceptible to humans induced threats. This includes fishermen shooting them due to feeling threatened in areas where they take their fish off their hooks, and the orcas being actively hunted for meat in coastal fisheries in Japan, Greenland, Indonesia, and the Caribbean islands. They can also become entangled in fishing nets.
Further threats to orcas that are not directly attacking the animal includes overfishing, which results in loss of habitat and food for the killer whales. They can also be contaminated by oil spills, and can be disturbed by vessels and boats which interrupt their sound calls. This includes boats that take humans out whale watching.
The Orca As The Predator
They are sometimes called the ‘wolves of the sea’ because they hunt in packs like wolves. On average, an Orca eats 227 kilograms (500 pounds) of food each day.
Orcas prey on a diverse array of species. However, specific populations show a high degree of specialization on particular prey species. For example, some populations in the Norwegian and Greenland sea specialise in herring and follow that fishes migratory path to the Norwegian coast each autumn. Other populations in the area prey on seals. In field observations of the resident whales of the northeast Pacific, salmon accounted for 96% of animals’ diet, with 65% of the salmon being the large, fatty Chinook. They have been observed to swim through schools of the smaller salmon species without attacking any of them.
Although resident Orcas have never been observed to eat other marine mammals, they are known to occasionally harass and kill porpoises and seals for no apparent reason.
Fish-eating Orcas prey on 30 species of fish, particularly salmon (including Chinook and Coho), herring, and tuna, as well as basking sharks, oceanic whitetip sharks and smooth hammerheads. In New Zealand killer whales have been observed hunting stingrays as well. Cephalopods, such as octopuses and a wide range of squids and reptiles, such as sea turtles, are also targets.
Groups of Orcas attack even larger cetaceans such as Minke Whales, Grey Whales, and very occasionally Sperm Whales or Blue Whales. Orcas generally choose to attack whales which are young or weak. However, a group of five or more Orcas may attack healthy adult whales. Bull Sperm Whales are avoided, as they are large, powerful and aggressive enough to kill orcas.
When hunting a young whale, a group of Orcas chases it and its mother until they are both worn out. Eventually the Orcas manage to separate the pair and surround the young whale, preventing it from returning to the surface to breathe. Whales are typically drowned in this manner. Pods of female Sperm Whales can sometimes protect themselves against a group of Orcas by forming a protective circle around their calves with their flukes facing outwards. This formation allows them to use their powerful flukes to repel the Orcas. Hunting large whales, however takes a lot of time, usually several hours. Orca cannibalism has also been reported.
Other marine mammals prey species include most species of seal and sea lion. Walruses and Sea otters are taken less frequently and Polar bears are rarely taken.
Fish-eating Orcas in the North Pacific have a complex but extremely stable system of social grouping. Unlike any other mammal species whose social structure is known, Resident Orcas of both genders live with their mothers for their entire lives. Therefore, Orca societies are based around matrilines consisting of a single female (the matriarch) and her descendants. The sons and daughters of the matriarch form part of the line, as do the sons and daughters of those daughters. The average size of a matriline is nine animals.
Because females can live for up to ninety years, it is not uncommon for four or even five generations to travel together. These groups are highly stable. Individuals split off from their matrilineal group only for up to a few hours at a time, in order to mate or forage. No permanent casting-out of an individual from a matriline has ever been recorded.
Check out more of our Galapagos Marine Life posts!