Why are crows said to be so smart?

KohakuPeople often say crows are clever. What kind of research showed that, I wonder?

The answer in 30 seconds

I've summed up what we know in 30 seconds.

Crows are called smart because research has confirmed that they can tell human faces apart and remember them for years, and that they make and use tools. We also know that information about dangerous people spreads to other crows and to their young. However, it is considered difficult to compare how "smart" animals are on a single scale.

A large-billed crow standing on a mossy tree — A large-billed crow, a common crow in Japan (the experiments in this article used American crows).Photo: Tisha Mukherjee / CC BY-SA 4.0 / Wikimedia Commons

Telling faces apart and remembering them

A research team at the University of Washington in the United States ran an experiment in which people wearing masks caught wild American crows (a different species from the large-billed crows often seen in Japan), put marker bands on their legs, and released them. After that, the crows began to scold and watch out for anyone wearing that mask, while reacting much less to people in other masks. The university reports that crows remember people who frightened them for years.

Word about dangerous people spreads

In this study, even crows that had never been caught started scolding the dangerous mask. Young crows that grew up watching their parents scold reacted the same way. At one site, the share of crows scolding doubled over about 5 years and spread to places at least 1.2 kilometers away. Crows are thought to learn from the behavior of other crows, too.

Figure: How word of a dangerous person spreads

KohakuSo they even learn about people they've never met, from other crows.

Some crows make tools

New Caledonian crows, which live on the island of New Caledonia in the South Pacific, make tools by snapping off small twigs and carving the tip into a hook with their beaks. They use these tools to pull food out of holes in trees. A researcher at the University of Auckland in New Zealand recorded in detail how wild crows make them in steps: choosing the material, preparing it, and carefully carving it.

Figure: How a hooked tool is made

Brain activity similar to ours

Another University of Washington study used brain imaging to look at how crows' brains work. When the crows saw the mask of a person who had frightened them, a region very similar to the part linked to fearful memories in humans and other animals became active. However, it is hard to rank how smart each animal is on a single scale, and research is still going on.

Want to know more?

According to a researcher at the University of Auckland, carefully carving a tool into shape had not been known in any animal other than humans before.
In observations of New Caledonian crows making tools, adult crows and young crows still depending on their parents made tools in similar steps.
Based on how crows' brains reacted to the mask of a person who had cared for them, a University of Washington researcher says it is important to always treat animals in our care with the same kindness.

KohakuRemembering faces, learning from each other, making tools. Research is confirming the cleverness of crows, little by little.

Quick quiz: test yourself

Why are crows said to be smart?

Show the answer

They are proven the smartest animal
They are big and strong
They remember faces and use tools

They remember faces and use tools Studies show crows can tell human faces apart and remember them for years, and that they make and use tools.

Sources

Crows react to threats in human-like wayUniversity of Washington（UW News）
Social learning spreads knowledge about dangerous humans among American crowsProceedings of the Royal Society B（PubMed）
The crafting of hook tools by wild New Caledonian crowsProceedings of the Royal Society B（Europe PMC）

This article was written after checking the sources above as of 2026-10-03. Explanations may change as research progresses. Photo credits are shown below each photo.