Killer ‘whales’ are actually a species of dolphin (the confusion stems from the Spanish, who called them ‘whale killers’). Unlike most whales, they're gregarious, have teeth and eat large animals (including whales) rather than krill or plankton. The Romans knew them as orcas (‘demons from Hell’).
Killer whales are strong, fast (35mph) and use echolocation to hunt in darkness. What really sets them apart from other hunters is they plan, improvise, work in teams and even offer internships to youngsters.
Killer whales need a lot of food: 230kgs (500lbs) a day. They hunt fish; sharks (which they flip upside-down to induce a paralysis called ‘tonic immobility’); and seals (which they knock off ice floes into the water). Unlike most species, killer whales have a lower life expectancy in captivity than in the wild, about 25 years. After a few years, males’ dorsal fins go floppy from lack of exercise.
Baby killer whales scream until they learn other vocalisations from their mother.
The killer whale is the wolf of the ocean and hunts in packs.
Newborn killer whales don't sleep for a month after birth.
To catch a seal, orcas (killer whales) push down on the edge of an ice floe so that it slides off. If a single orca can’t dislodge one, it enlists the rest of the pod. Together, they shunt the floe away from the ice pack. One orca goes to the far side of the floe and blows through its blowhole to signal the attack. The rest swim at full speed, line abreast, towards the floe, creating a bow wave. At the last moment, they duck under the floe. The wave breaks over the top, washing the seal into the water.
Youngsters remain on the sidelines, watching and learning. Orcas sometimes teach their young by repeatedly catching and releasing a seal so that they can study the technique. In 2005, an orca was seen regurgitating fish onto the water as bait for gulls, which it then caught. Four others copied the strategy.
Killer whales' favourite delicacy is whale's tongue.
The only other animal with a clear-cut menopause followed by many more years of life is the killer whale. It’s a puzzle in biology: why have human and killer whale females evolved to have such a long period (nearly half their normal lifespan) between the menopause and their death? It would make much more sense for them to die early, or be able to reproduce for longer.
Elsewhere in the animal kingdom, reproductive potential simply tails off; females just produce fewer young as they age. The ‘mother hypothesis’ suggests that a mother will do better in the genetic stakes by avoiding the risks associated with childbirth and additional child-rearing and instead concentrate on raising the kids she already has. A better answer may lie in the ‘grandmother hypothesis’, which argues that a generous post-reproductive life span makes sense if a grandmother improves the survival and reproduction of her grandchildren, thus ensuring continuation of her own genes.
Willy from Free Willy was played by an Orca called Keiko. He was set free to great fanfare in 1998, but never integrated back into killer whale society due to the fact that he had been living with humans for virtually his entire life. He eventually skulked back to captivity, dying of pneumonia inside an open-access pen in a Norwegian inlet in 2003.
Dogs can be trained to smell killer-whale poo from a mile away.
No killer whale has ever killed a human in the wild.