The Average IQ of a Monkey: How Smart Are Monkeys?

Monkeys are not apes (and it matters here)

A surprising amount of confusion comes from lumping monkeys and apes together. They are different groups of primates.

The quickest tell is the tail: almost all monkeys have one, and apes never do (apes have only a tailbone). Monkeys are generally smaller and narrow-chested; apes are larger, broad-shouldered, and built to swing through trees. According to Britannica, apes are actually more closely related to Old World monkeys than those monkeys are to New World monkeys.

Why does this matter for intelligence? Because chimpanzees, gorillas, bonobos, and orangutans — the great apes — are the primates that consistently top cognitive tests, and they are not monkeys. When people picture a "genius monkey" cracking a puzzle, they are usually picturing a chimp. So on the intelligence ladder, monkeys sit a rung below the apes most of the time.

What monkeys are genuinely good at

Here is the honest and impressive part. Strip away the fake IQ numbers and monkeys show real cognitive muscle.

Capuchins are stone-age tool users. Bearded capuchins in Brazil's Serra da Capivara National Park crack open cashew nuts using quartzite cobbles as hammers and tree roots or rocks as anvils. A 2019 archaeological study led by researchers at UCL and the University of São Paulo recovered 122 stone artifacts and dated capuchin tool use back roughly 3,000 years — about 450 generations — making it the oldest known non-human archaeological site outside Africa. In the wild, capuchins even select hammer stones of the right weight and hardness for the job, which points to a real grasp of cause and effect.

Macaques track numbers and monitor their own memory. Rhesus macaques can compare quantities and perform rough arithmetic. Their precise number system tops out at about four items held in mind at once, and beyond that they compare approximate magnitudes — the same "number sense" that underlies human math, which suggests deep evolutionary roots. Studies also show macaques have metacognition: in uncertainty tasks they will decline a hard trial rather than guess, effectively signaling "I'm not sure" — a sophisticated awareness of their own knowledge.

Old World monkeys can rival apes on many tests. A well-known PLOS ONE study using the Primate Cognition Test Battery compared Old World monkeys with great apes and found largely comparable results. Chimpanzees pulled ahead mainly in spatial understanding and tool tasks — not in social cognition. So the monkey-below-ape gap is real but narrower than the stereotype, and it depends heavily on which ability you test.

The honest bottom line

Monkeys are intelligent animals with a distinct profile: strong causal reasoning and tool use in capuchins, solid number sense and self-monitoring in macaques, and social smarts across many species. On direct comparisons they usually land just below the great apes, especially on physical problem-solving and tool use.

But none of that converts into a human IQ number. If a source hands you a specific "monkey IQ," treat it as entertainment, not science. The scientifically honest statement is: monkeys don't have an IQ — they have abilities, and those abilities are worth respecting.

And if the question got you curious about where your own reasoning stands, that is something an IQ test genuinely can measure — because it was built for you.

Frequently asked questions

Q: What is the average IQ of a monkey?

A: There isn't one. IQ tests are designed and normed on humans, so they can't produce a valid score for a monkey. Any specific number you see online is invented. Scientists instead measure specific abilities like tool use, memory, and number sense.

Q: Are monkeys smarter than apes?

A: Generally no. Great apes such as chimpanzees and gorillas usually outperform monkeys, especially on tool use and spatial problem-solving. But Old World monkeys rival apes on several tasks, so the gap is real but narrower than people assume.

Q: What is the smartest monkey?

A: Capuchins are strong candidates. They use stone tools in the wild, select hammers by weight and hardness, and solve causal puzzles. Rhesus macaques also stand out for number sense and self-awareness of their own memory.

Q: Can a monkey pass a human IQ test?

A: No. Human IQ items rely on language, schooling, and cultural knowledge a monkey doesn't have. Researchers use species-appropriate tasks — touchscreens, puzzle boxes, food-reward tests — never human IQ tests.

References

• Proffitt, T., et al. (2019). "Wild monkeys flake stone tools." / UCL News: Capuchin monkeys have been using stone tools for around 3,000 years
• Schmitt, V., Pankau, B., & Fischer, J. (2012). Old World Monkeys Compare to Apes in the Primate Cognition Test Battery. PLOS ONE
• Encyclopaedia Britannica: What's the Difference Between Monkeys and Apes?
• Nature / Scitable: Primate Cognition

Last updated: July 13, 2026