Orca IQ: How Smart Are Killer Whales? Brain Size, Behaviour and Limits
How smart are killer whales? An orca brain averages about 5.6 kg in females and 7.1 kg in males, yet ranks below the bottlenose dolphin and humans for its body size. What is known about neurons, leadership by older females and pod sounds, and why orcas have no IQ.
How smart are killer whales? Highly capable, but they have no IQ. A killer whale’s brain averages about 5.6 kg in measured females and 7.1 kg in males, among the heaviest on Earth. For its body size, though, the orca ranks below the bottlenose dolphin and humans. What stands out is behaviour: pods keep their own sounds, and older females lead the group when it hunts salmon.
Below: how big an orca’s brain is, how it compares by body size, what is known about neurons, what orcas do that looks like intelligence, and why none of it adds up to an IQ.
How smart are killer whales?
Very capable by every measure scientists have used, but not measurable on a human scale. An IQ is a position within a norm sample of people. No norm sample of orcas exists, so there is no orca IQ. Researchers instead look at brain size, behaviour in the wild and a few experiments. The sections below take them one by one.
How big is an orca's brain?
One of the biggest on the planet. A 2016 paper by Cozzi and colleagues says that sperm whales and killer whales “possess the heaviest brains on the planet”. It tabulates measured killer whale brains from earlier research by Ridgway and Hanson.
| Measure | Result | Note |
|---|---|---|
| Average brain, adult female | 5,606 g (about 5.6 kg) | Body length about 5.4 m |
| Average brain, adult male | 7,093 g (about 7.1 kg) | Body length about 6.5 m |
| Largest brain in the table | 9,300 g (about 9.3 kg) | A whale 7.19 m long |
| Cerebellum share of brain mass | almost 14% | About 7% in the sperm whale |
The sample is small, 10 specimens in the table, so treat the averages as a guide. The same authors note that comparing orca and sperm whale brains is hard because their cerebellums differ so much.
Do orcas have bigger brains than humans?
Yes in total weight, no relative to body size. A bigger animal needs a bigger brain just to run a bigger body, so scientists compare brain size with body size using the encephalization quotient (EQ). An EQ of 1 means the brain is the size expected for the body; above 1, larger than expected.
Cozzi and colleagues give killer whales an EQ of 2.71 for females and 2.33 for males. Their chart ranks humans highest, then the bottlenose dolphin, with the orca clearly below both. Elephants and killer whales are the only large mammals, the authors write, weighing far more than a ton with an EQ above 1. Our guide to dolphin IQ covers the species ranked above the orca.
How many neurons does an orca have?
We found no published count. The best-known study of dolphin-family brains, by Mortensen and colleagues in 2014, counted neocortical neurons in the long-finned pilot whale, a close relative: about 37.2 billion, which the authors call “almost twice as many as humans”. The study reports a pilot whale figure and none for the orca.
Do not assume an orca matches the pilot whale. The pilot whale figure shows that dolphin-family brains can pack many neurons into a large cortex, but it does not give a count for the orca. For a similar story in another species, see our guide to elephant IQ.
What do orcas do that looks like intelligence?
Three things stand out, each from published research:
- Leadership by older females. A 2015 study in Current Biology found that “postreproductively aged females lead groups during collective movement in salmon foraging grounds”. Their leadership “is especially prominent in difficult years when salmon abundance is low”. The authors suggest that this ecological knowledge may help explain why female killer whales live long after they stop breeding.
- Pod-specific sounds. NOAA Fisheries says “each pod in the Pacific Northwest possesses a unique set of sounds”.
- Mirror experiments. A 2001 study of killer whales, false killer whales and sea lions found “contingency checking” in killer whales, and said that killer whales and false killer whales “appear to possess the cognitive abilities required for self-recognition”. That is not the same as passing a mirror test.
The orca is also a dolphin. NOAA states that “the killer whale is the largest member of the dolphin family”. So much of what we know about dolphin minds is relevant, and our guides to chimpanzee IQ, gorilla IQ and octopus IQ show how other species are measured.
Where would your own score land?
Take the IIF-certified assessment and get your score with the scale it was measured on, the percentile it corresponds to and the confidence range around it — the three figures most online tests leave out.
Find your IQ score now! →Is a bigger brain a smarter brain?
Not by itself. The Cozzi paper warns that “the EQ is not per se a sign of intelligence”, and notes that many EQ figures “rely on single measures, often extrapolated from old-to-very-old sources”. Body weights used in the calculation are also estimates; one table in the paper gives three different weights for the same whale.
Our review of brain size and IQ in people shows how modest the link is even inside one species. Across species the problem is bigger: different animals use brains differently, which is why researchers look at behaviour as well as size. See also our study of the smartest animals.
Is there an orca IQ?
No. IQ tests are built for people: a sample of people takes the test, and scores are placed against that sample. Orcas cannot take such a test and have no norm group. Any page that prints an “orca IQ” is making up a scale. For how a norm sample defines the average, see the average IQ in the USA; for how a human score is placed on a curve, see the IQ bell curve and the IQ percentile calculator. To test your own reasoning, take the IQ test.
Quick answers
- How smart are orcas? Highly capable, with large brains, leadership by older females and pod-specific sounds, but no IQ can be measured.
- How big is a killer whale brain? About 5.6 kg for females and 7.1 kg for males in the measured specimens, up to 9.3 kg in the largest.
- Do orcas have more neurons than humans? No orca count exists. A relative, the long-finned pilot whale, has about 37.2 billion neocortical neurons.
- Are orcas dolphins? Yes. NOAA calls the killer whale the largest member of the dolphin family.
The bottom line
Orcas have one of the heaviest brains on Earth and show learned, shared behaviour, but their brain is smaller than expected for their body size and no one has counted their neurons. They are intelligent animals, and “orca IQ” is a number nobody can measure.
Sources
- Cozzi et al. (2016), International Journal of Comparative Psychology: killer whale brain mass and encephalization.
- Mortensen et al. (2014), Frontiers in Neuroanatomy: Quantitative relationships in delphinid neocortex.
- Brent et al. (2015), Current Biology: leadership and the evolution of menopause in killer whales.
- NOAA Fisheries: killer whale species page.
- Ridgway and Hanson (2014), Brain, Behavior and Evolution 83(4); Delfour and Marten (2001), Behavioural Processes 53(3).
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