The Orca (scientific name: Orcinus orca) is classified as a toothed whale due to its suborder. Its specific family, though, is Delphinidae, making the species oceanic dolphins.

If you look closely, you’ll see the resemblance with dolphins as orcas have a bulbous, beak-like shaped head and a compact body. This makes them aerodynamic and efficient in the water.

You may know this species by the unfortunate nickname it has been tagged with, ‘killer whale’. It’s said that name was coined by sailors who spotted orcas preying on other marine mammals and called them ‘whale killers’ which then morphed into ‘killer whales’.

Orcas are distinctively black and white with a large dorsal fin. They are up to 6-8 metres long and can weigh up to 6 tonnes in weight.

The average lifespan for male orca in the wild is about 30 years but they can live up to at least 60 years. Females typically live about 50 years, but can live up to at least 90 years in the wild.

Where do they live?

Orca are found in areas all over the world. They’re most abundant in colder waters such as those in Antarctica, Norway, Iceland and the Pacific North West (off the coasts of Alaska, Canada, Washington State etc.) They can be spotted out in the open ocean, usually when migrating, but are most often found in coastal waters.

In addition to habitats in colder waters, orca have also been seen in warm water areas such as Australia, the Galapagos Islands, California, the Bahamas and the Gulf of Mexico. And they are found in more temperate waters such as South Africa and New Zealand.

Orca are also spotted in the summer months (June-September) in the Strait of Gibraltar, at the tip of Southern Spain, where they feed on blue tuna in the waters. And they are spotted sometimes off the west coast of Ireland and Scotland.

It’s estimated that there are 50,000 orca globally.

Intelligent and social creatures

Orca have the second largest brains among all animals (after the sperm whale), weighing as much as 15 pounds.

They are also incredibly cultural – teaching their offspring hunting techniques and teaching complex languages to each other. Their bio-sonar, or echolocation, abilities are really impressive.

Orca make sounds that travel underwater until they encounter objects, then echo back, revealing their location, shape and size. There’s still a huge amount to be discovered about how echolocation operates in orcas.

Orca are also incredibly curious, playful and have an ability to problem-solve.

They are highly social and are known to travel with as many as four generations. These groups are highly stable and matrilineal. A female orca gives birth to one calf every three to ten years. It’s partly due to this slow period of reproduction that the species has trouble repopulating.

What do they eat?

Some orca only eat fish while others hunt other prey such as seals, dolphins, penguins or even sharks or larger whales (this is a lengthy task for orca involving many hours of effort and hunting together as a group).

Threats to orca


Orca are at risk of becoming entangled in fishing gear. When this happens, they may be dragged or forced to swim with attached gear for long distances or may be anchored in place and unable to feed. Death is a very real risk when cetaceans are fatigued, unable to feed and/or severely injured.

Disturbance from vessels and sound

Orcas use echolocation to help them communicate with other whales, to feed and to orientate themselves. Noise from vessels, as well as from military and industrial activities can interfere with their echolocation.

When vessels are present, orcas hunt less and need to travel more. Collision with vessels can cause serious injury and/or death to all marine mammals, including orca.


Orcas are highly intelligent and social animals and it’s increasingly clear that orcas do not thrive or survive well in captivity, as part of marine park entertainment. Outcomes for the animals can include a much shortened life span, boredom, stress, anxiety, self-mutilation, stillbirths and illness.

In 2013, the documentary film Blackfish told the story of several whales held in captivity. It particularly focuses on a wild-caught orca named Tilikum who was involved in the death of two marine park trainers. The film includes testimony from cetacean specialists and former SeaWorld trainers who argue that Tilikum’s stress from captivity directly led to his aggression.

Lack of food

Overfishing and habitat loss directly causes a reduction in the amount of prey available to many orca. Research shows that without enough food, orca are more likely to experience decreased reproductive rates and increased mortality rates.


Our ocean has become more polluted, as the result of increased industrialisation and the impacts of human activity. Chemical contamination (from sources such as wastewater treatment plants, sewer outfalls, diesel/oil spills and pesticide applications) enters ocean waters and has an effect right through the food web, beginning at the top with species like the orca.