Commonly referred to as the ‘killer whale’, the orca (Orcinus orca) is a fearsome but misunderstood creature. I’m not a huge fan of the term ‘killer whale’, so I will only be using ‘orca’ in the rest of this post. The orca is a toothed mammal which actually belongs to the dolphin family and not the whale family. They are the largest species of dolphin, reaching up to 10 metres (33ft) in length – around the same length as your average bus.
Boldly marked, these marine mammals are easily recognisable. They have a black and white colouring, with a distinctive white patch just above each of their eyes. In addition, they have a tall dorsal fin, up to 1.8 metres tall, which can be used to identify individuals. Orcas are one of the world’s most widely distributed species (besides humans); they can be found in all of our oceans and nearly all seas – exceptions being the Baltic and Black sea. Their vast distribution is a testament to the orca’s fantastic adaptability.
Orcas are at the top of the marine food chain – making them apex predators. They feed on fish, seals, sea lions, sharks and even other cetaceans (dolphins, whales and porpoises). However, their diet varies from location to location, as different populations have specialised to hunt certain prey.
Known as the wolves of the sea, orcas have a developed a cunning and effective hunting strategy. They hunt in pods, some pods can contain up to 40 individuals. These pods are able to wipe out whole schools of herring, huge elephant seals, great white sharks and even sperm whales. Orcas will use echolocation to communicate and hunt, making sounds travel underwater until they encounter an object, then these sound waves will bounce back, revealing the object’s location, size and shape. When these mammals work together they make a formidable force.
However, orcas are not just excellent predators; they also have a caring, sociable and empathetic side. Adolescent females often assist mothers in looking after their young and each pod makes distinctive noises to greet and communicate with each other. Moreover, orcas are highly intelligent. They live in complex societies and can be very playful – both with other orcas and humans. In fact, they are such an intelligent and complex species that there are growing concerns about keeping orcas in captivity, especially just for human entertainment.
Hennessy, K., Wiggins, V. (2014) Animal Encyclopedia: The Definitive Visual Guide. 2nd edn. London. Dorling Kindersley.