fabian s. klinkeWhy Crows Are as Smart as 7 Year Old Humans
Source: Why Crows Are as Smart as 7 Year Old Humans, Real Science, 16:02, uploaded 2022-05-31, category Science, playlist index 424.
Real Science opens with the usual suspects in animal intelligence: primates using sticks and rocks, orcas hunting together, and dogs reading the people around them. The list carries an assumption about where intelligence should appear. Large-brained mammals that eat meat and live in close social groups seem to have the right conditions for it.
Crows interrupt that picture. Corvids use tools, drop nuts onto roads so cars crack them, recognise faces, remember people who treat them badly, and copy sounds. The video says that some of their problem-solving skills match those of a seven-year-old child. It then asks two linked questions: how do scientists measure intelligence in a bird, and does the bird brain reach that result through the same machinery as a mammal brain?
The water-tube tests
The corvid family includes crows, jays, ravens, rooks, and magpies. The video singles out the New Caledonian crow as the most capable species in the family and moves quickly from reputation to experiment.
In a 2014 study, crows faced tubes in which a treat floated on water beyond their reach. When one tube held water and another held sand, the birds dropped rocks into the water tube until the level rose high enough to reach the food. They ignored the sand. When researchers offered objects with different densities, the birds chose objects that sank. When two tubes held different water levels, they worked on the tube with the higher level because fewer objects would raise the treat within reach.
The authors, as the video presents them, compare the crows’ performance with that of five- to seven-year-old children. The comparison has a boundary. The birds struggled with a wide tube beside a narrow one and with a hidden U-bend that connected the reward tube to another tube. Children solved these counter-intuitive arrangements consistently at about eight years old. The same animal can therefore look older or younger depending on the physical relation a test requires it to understand. The age label describes performance on a task. It does not give the crow a human-style general intelligence score.
Tools with several parts
The New Caledonian crow also constructs tools. When a stick is too short to reach food inside a puzzle box, the bird can fit one stick into the hollow end of another and make a longer tool. One crow in the video makes tools with three and four parts. The source says that this kind of compound construction has been seen outside humans in only a few captive great apes, which is why it has carried such a strong association with human intelligence.
Tool use alone does not explain the comparison with children. A crow has to select material, understand the relation between length and reach, and assemble a new object for a particular problem. Those steps give the video its first case for flexible reasoning.
Planning across a delay
The next studies concern a harder ability: choosing an action now because it will produce a better reward later. In a 2020 experiment, New Caledonian crows first saw one of three puzzle boxes that they already knew how to open with a particular tool. Researchers removed the birds for five minutes, then offered five objects: the tool for each box and two distractions. After the crow chose an object and waited another ten minutes, it returned to the test area. The birds often selected the tool that matched the box they had seen and carried it back into the room.
A related test placed a locked box with a good treat beside an immediate food reward that was easier to take but less appealing. The birds usually kept the correct tool and waited for the better food. The video compares this with human development. The ability appears in children around five years old, although it does not appear reliably in every child at that age and may take longer for some.
Memory of the earlier box, a choice among distractions, and a delayed result all enter the task. The source uses these experiments to place crows alongside the most capable primates. It then turns from behaviour to anatomy, since a bird that performs these tasks has to do so with a brain that evolved on a separate branch from ours.
A bird brain without a cerebral cortex
Birds and mammals split from a common ancestor roughly 320 million years ago. Both lineages developed a pallium, the grey and white matter covering the brain. In mammals, the pallium became the layered cerebral cortex, where the source places learning, memory, sensory perception, and conceptual thought. Birds do not have a mammalian cerebral cortex.
That absence once made bird intelligence seem improbable. The video points to a 2020 study that found a similar organisation in the bird pallium. Its fibres and circuits run horizontally and vertically in a pattern that resembles the mammalian neocortex. The arrangement gives the source a possible explanation for how a bird can perform work associated with a mammal brain without possessing the same named structure.
Brain size supplies another correction. The absolute size of an animal’s brain says little on its own, so the video first compares brain size with body size. Humans and dolphins have the largest relative brains among mammals, whilst parrots and crows have the largest among birds. The more useful measure may be neuron density. Tightly packed neurons can give signals shorter distances to travel. A 2016 study cited by the video found that some birds, including corvids, have roughly twice as many neurons as primates with similarly sized brains, bringing their counts closer to those of larger primates.
The family life behind the skill
The anatomy accounts for some of the crows’ ability. Their upbringing may account for the rest. New Caledonian crows can depend on their parents for food for up to two years, which gives young birds prolonged access to adults that make and use tools. Skills can pass from parent to offspring through repeated observation and practice. In some crow species, young birds even help defend a parent’s new nest.
This raises a problem for the social intelligence hypothesis. Chimpanzees live in large social groups and track many relationships outside their immediate families. Dogs, wolves, and orcas also face complicated social lives. Many adult corvids do not. New Caledonian crows mate for life and often spend little time with other adults. Other corvids forage or roost in groups and mob predators together, although those groups do not show the same stable hierarchy or network of relationships found in chimpanzee societies.
The missing social pressure may appear during adolescence. Ravens and other corvids form larger juvenile flocks before pairing with a mate. The video calls these groups juvenile gangs. Young birds bully one another, fight, and establish ranks that determine access to better food. A bird that later lives in a small family unit may spend its formative years keeping track of a crowded and shifting social world.
Ravens, wolves, and shared attention
Corvid intelligence also reaches across species. Around Yellowstone National Park, ravens have been observed playing with wolves, especially wolf pups. The birds pull at sticks, tease the pups into jumping, and sometimes tug their tails. The source presents the encounters as play and reports the possibility that individual ravens form special relationships with individual wolves. That familiarity may help the ravens approach a pack and scavenge from its kills.
The same willingness to work across species has led people to test practical cooperation. Several companies are developing devices that train crows to collect cigarette butts or other rubbish by giving them food when they place an object into a machine. A French theme park trained six rooks to pick up litter four days a week under the supervision of its falconer.
The arrangement carries an ethical question that the video leaves open. The people involved say the work helps the environment, teaches humans to cooperate with another species, and gives the public a reason to notice corvid intelligence. The birds are also performing a task that humans have left undone. The source records both sides without settling whether the exchange respects the animals or turns their ability into cheap labour.
What the evidence can support
Real Science closes by widening the question. Studying crows can teach researchers how brains develop and how intelligence can emerge from different anatomy. Other small-brained animals may also carry abilities that researchers have missed because intelligence has been measured through human expectations and familiar mammalian examples.
The age comparisons in the video describe success on selected puzzles. They do not establish that a crow thinks like a seven-year-old human, and the failed water-tube tasks show why the distinction matters. The video gives numbered studies and links in its description, yet it does not provide sample sizes, detailed controls, or a full account of how each experiment supports its wider claim. The caption track also contains small transcription errors. This note keeps the studies, dates, neuron counts, developmental claims, and cross-species comparisons as claims made by the source rather than as independently checked results.
Further reading / references
The video description supplies these twenty numbered references. Their numbering is preserved here; the source does not provide titles for all of them.