What is the Smartest Animal

Short answer

• There is no scientifically settled single winner for the smartest animal. The answer depends on which measure of intelligence is used.
• Chimpanzees are often described by researchers as the leading candidate overall, based on their broad range of tool use, social learning, and problem-solving.
• Bottlenose dolphins, elephants, New Caledonian crows, African gray parrots, and octopuses each lead on at least one well studied measure, from self-recognition to tool manufacture to communication.
• Intelligence is measured through problem-solving, tool use, memory, communication, social learning, and self-recognition, not brain size alone.
• Several species show different kinds of high intelligence, shaped by the lives they evolved to live.

If you ask ten people to name the smartest animal, you will probably hear several different answers: the chimpanzee, the dolphin, the elephant, the octopus, or the crow. Each answer can point to real research, and that is the first clue that the question itself needs unpacking. Scientists do not agree on one winner, because intelligence is not one thing. It is a bundle of abilities, and different animals lead on different measures.

This article explains how researchers measure animal intelligence, what the evidence shows for the leading candidates, and why single-species rankings should be treated with caution. Where a superlative appears here, it is attributed to a specific study or measure, not presented as a settled fact about the whole animal kingdom.

Why There Is No Single Winner

The trouble starts with the word smart. In everyday speech, it usually means something like quick thinking or clever problem-solving. In animal cognition research, it has to be broken into testable parts before it can be studied at all. A researcher cannot simply ask an octopus and a chimpanzee the same question and compare their answers, because the two animals perceive the world through different senses, move in different ways, and solve different survival problems.

A chimpanzee that fails a test designed around color vision might fail for reasons that have nothing to do with intelligence. An octopus tested on land is at a similar disadvantage. Good research therefore designs tests around what each species can sense, and compares performance on the same underlying ability, such as remembering a location, rather than on the same physical task.

A second problem is that intelligence evolved more than once, for different purposes. Primates evolved large, socially complex brains in part to manage group life. Corvids, the bird family that includes crows and ravens, evolved dense, highly connected brains that support flexible problem-solving despite a very different brain structure from mammals. Octopuses evolved intelligence along a separate branch of the tree of life entirely, as solitary hunters that rely on camouflage, exploration, and manipulation of objects. Asking which is smartest is a bit like asking whether a hammer or a saw is the better tool.

A third problem is the evidence base itself. Chimpanzees and bottlenose dolphins are among the best studied species, while others, such as many parrot species, have been studied intensively only through a few famous individuals. A species can look less intelligent simply because researchers have not yet designed the right test for it. Rankings built from uneven evidence should therefore be read as snapshots of current research, not as final verdicts. The honest answer is a comparison across measures, and that is what the rest of this article provides.

How Scientists Measure Animal Intelligence

Researchers use several families of tests. Each one captures a different slice of cognition, and each one has limits that matter when results are compared.

Problem-solving and flexibility

Problem-solving tests ask whether an animal can reach a goal it cannot reach directly. Classic examples include retrieving food from a puzzle box, choosing the right tool for a task, or finding a new route after a familiar route is blocked. The strongest evidence comes when an animal solves a new version of a problem, not merely a version it has been trained on, because that suggests flexible thinking rather than memorized routine.

Flexibility matters because many animals can learn a fixed sequence through repetition. An animal that adjusts when the setup changes or combines two known actions into a new solution is showing something more than rote learning.

Tool use and tool manufacture

Tool use means using an external object to achieve a goal, such as using a stick to extract insects or a stone to crack a nut. Tool manufacture goes a step further: the animal shapes or combines materials to make a tool suited to the task. Researchers treat spontaneous manufacture, especially with unfamiliar materials, as stronger evidence of planning than using a ready-made object found in the environment.

Tool use is not, by itself, proof of high general intelligence. Some tool behaviors are highly specialized and appear in species that do poorly on other tests. But when tool use is combined with flexibility, social learning, and planning, it becomes part of a strong case.

Communication and social learning

Communication tests examine whether animals share information in structured ways. Researchers look for learned signals used consistently, for signals that refer to specific individuals or objects, and for evidence that receivers understand those signals rather than merely reacting to a sound.

Social learning tests ask whether animals learn by watching others. In the wild, this shows up as local traditions: a feeding technique used by one group but not by a neighboring group of the same species. In the laboratory, it shows up when a naive animal copies a demonstrated solution, sometimes improving on it. Species with strong social learning can accumulate knowledge across generations.

Memory

Memory tests cover several kinds. Spatial memory is the ability to remember locations, such as where food is hidden or where a safe den lies. Episodic-like memory is the ability to remember a specific past event, including what happened, where, and when. Working memory is the ability to hold information in mind while using it, for example while solving a multi-step puzzle. Memory tests are among the easiest to run fairly across species, but also among the hardest to interpret, because a superb memory for one kind of information, such as hidden seed locations, does not imply general intelligence.

Self-recognition

The best known self-recognition test is the mirror test, developed by psychologist Gordon Gallup Jr. in 1970. In the classic version, an animal is allowed to become familiar with a mirror, then is marked with a dye spot in a place it cannot see without the mirror, such as the brow or ear. If the animal uses the mirror to investigate the mark on its own body, rather than treating the reflection as another animal, researchers take that as evidence of mirror self-recognition.

The mirror test is useful, but it has well known limits. It depends heavily on vision, so it disadvantages animals that rely mainly on smell, hearing, or touch. It also tests only one narrow form of self-awareness, and failing it does not prove that an animal lacks self-awareness in other forms. Passing it, on the other hand, is widely treated as meaningful evidence, because so few species pass under controlled conditions.

Brain size and structure

Brain size alone is a poor measure. Larger animals tend to have larger brains, and much of that brain tissue is devoted to running a larger body. Researchers therefore also consider brain size relative to body size, the organization of brain regions, and, in birds, the density of neurons in the forebrain. Even these refined measures are only rough guides. They can suggest which species are worth testing closely, but they cannot settle a ranking on their own. A species with a modest brain can outperform a large-brained species on a specific task, and the octopus is the clearest example.

The Leading Candidates

Chimpanzees: the broadest case

Chimpanzees are often described by researchers as the leading candidate overall, and the breadth of their evidence is the reason. They are the closest living relatives of humans, and they show high performance across more measures than any other single candidate.

In the wild, chimpanzees use tools in varied ways. They fashion sticks to extract termites from mounds, use stones to crack open nuts, and modify leaves to serve as sponges for collecting water. Different groups use different tool kits, and young chimpanzees learn these techniques by watching older group members over years, which is evidence of social learning and cultural transmission.

In the laboratory, chimpanzees have solved multi-step puzzles, learned to use symbols, and shown strong memory performance. They were also the first animals shown to pass Gallup’s mirror test in 1970: chimpanzees familiar with mirrors used their reflections to groom parts of their bodies they could not otherwise see, and after being marked with dye on the brow and ear, they touched the marks while looking in the mirror. Control animals that had not had time to learn about mirrors did not do this. Chimpanzees also show complex social behavior, including cooperation, reconciliation after conflicts, and forms of helping that suggest they track what others can see or know. Together, these findings explain why chimpanzees top many researchers’ overall assessments: they perform strongly across many measures, not merely one.

Other great apes: orangutans and bonobos

Orangutans and bonobos share much of the same cognitive toolkit. Orangutans are known for careful problem-solving and tool use in the wild, and researchers have also reported mirror self-recognition in orangutans. Bonobos show notable social tolerance and communicative flexibility. Chimpanzees usually lead discussions because of the volume and breadth of chimpanzee research, not a proven gap in ability.

Bottlenose dolphins: communication and self-recognition

Bottlenose dolphins are the strongest marine candidate, and their case rests on communication, social complexity, and self-recognition.

Each bottlenose dolphin develops an individually distinctive signature whistle, shaped by vocal learning. Research from the University of St Andrews has shown that dolphins copy the signature whistles of others and that wild dolphins respond to hearing a copy of their own signature whistle by calling back, while not responding to whistles that are not their own. The researchers concluded that these learned identity signals are used as labels when addressing specific companions, a form of vocal labeling that is rare in nonhuman animals.

A later study from the same research group, published in Science Advances in 2022, showed that bottlenose dolphins can recognize individuals across senses: they investigated longer when a signature whistle playback matched a urine sample from the same individual than when it did not match. That points to a mental representation of a known individual that is not tied to a single sense.

Dolphins were also among the first non-primate animals reported to show mirror self-recognition, and they are known for cooperative hunting, cultural transmission of foraging techniques between generations, and flexible problem-solving in laboratory settings. Their social world is fluid, with individuals joining and leaving groups, which places heavy demands on recognizing individuals and tracking relationships.

Elephants: memory, self-recognition, and social care

Elephants make the case that intelligence is not only about puzzles and tools. Their strengths are memory, social knowledge, and self-recognition, supported by long lives and stable family groups.

The landmark elephant study was published in 2006 by researchers including Joshua Plotnik, Frans de Waal, and Diana Reiss, working with three female Asian elephants at the Bronx Zoo. The team placed a large mirror, about 2.5 meters square, inside the elephants’ yard. All three elephants investigated the mirror without treating their reflections as intruders, and they used it to inspect parts of their own bodies, including the insides of their mouths. One elephant, Happy, passed the mark test: after researchers painted a visible white mark on her forehead and a sham, invisible mark on the other side, she repeatedly touched the visible mark while looking in the mirror and ignored the sham mark.

Elephants are also known for long-distance social memory. Matriarchs, the oldest females in a herd, lead family groups and appear to draw on decades of experience, including knowledge of distant water sources during drought and recognition of other family groups. Combined with their helping behavior toward injured or distressed herd members, this paints a picture of intelligence built around social knowledge and memory rather than tool manufacture.

New Caledonian crows: tool manufacture and planning

If the contest were judged on tool manufacture alone, New Caledonian crows would have a strong claim. These birds, native to the Pacific island of New Caledonia, make and use tools in the wild, shaping twigs and strips of pandanus leaf into probes for extracting insects.

The most famous case is Betty, a New Caledonian crow studied at the University of Oxford. In 2002, researchers reported that Betty spontaneously bent a straight piece of wire into a hook to lift a small bucket of food from a vertical tube, after another crow had taken the hooked wire. At the time, this was presented as a striking example of insight and tool innovation with an unfamiliar material.

Later field research added an important qualification, and it is worth reporting because it shows how science corrects itself. Researchers from the University of St Andrews found that wild New Caledonian crows use similar bending techniques when shaping twig tools in their natural habitat. Betty’s solution may therefore have drawn on predispositions from her species’ habitual tool use, rather than being a wholly novel invention. That qualification does not erase the achievement, but it does show why single anecdotes should not carry a whole ranking.

More controlled evidence has since strengthened the crow case in a different way. A study from the Max Planck Institute for Ornithology and the University of Oxford showed that New Caledonian crows can create compound tools by combining two or more parts that are useless on their own, without training or assistance. The researchers noted that this kind of combination, which requires anticipating the properties of objects not yet seen, had previously been observed only in humans and great apes. Crows also show strong problem-solving, causal reasoning, and, in some studies, the ability to plan for future needs rather than acting only on present hunger.

African gray parrots: words, numbers, and concepts

African gray parrots show that a small brain can support abstract thinking. The best known evidence comes from Alex, an African gray studied for three decades by comparative psychologist Irene Pepperberg, first at Harvard and later at Brandeis University.

Alex learned more than 100 English labels and could identify about 50 objects, 7 colors, and 5 shapes. He could report quantities up to 6, use labels to request, refuse, and categorize items, and answer questions about sameness and difference, including whether two objects differed in color, shape, or material. In a study published in the Journal of Comparative Psychology in 2005, Pepperberg reported that Alex spontaneously used the label “none” to describe an absence of quantity on a tray, and then consistently identified zero quantity in follow-up trials. Pepperberg described this as a zero-like concept, not identical to the human concept of zero, but a genuine understanding of absence.

Alex’s case comes with a caveat that applies to much parrot research: it rests heavily on one intensively trained individual. Later work with other parrots has supported the general picture of parrot cognition, but Alex alone cannot prove that every African gray parrot thinks the same way. What his case does prove is that the avian brain, organized very differently from the mammalian brain, can support concepts, categories, and numerical reasoning that researchers once thought were beyond birds.

Octopuses: a separate evolution of intelligence

Octopuses are the most important candidate for a different reason: they show that high intelligence evolved independently, in an animal with no shared brain plan with vertebrates at all. An octopus has a central brain plus extensive nerve networks in its arms, allowing each arm a degree of local control while remaining under central direction.

The Natural History Museum, London, describes a 2011 experiment in which researchers tested whether an octopus could guide a single arm through a maze to reach food, with the arm out of water so it could not use chemical sensing to find the target. Most of the octopuses tested eventually succeeded, showing that visual information processed by the central brain could direct an arm. Octopuses have also demonstrated spatial learning in laboratory studies, remembering the location of an open burrow among several possible locations after a delay of a week.

Their documented maze learning, object manipulation, and rapid adaptation to new puzzle setups support their place among the leading candidates. Their weakness, relative to primates and dolphins, is social cognition: octopuses are largely solitary, so they show little of the cooperative complexity that defines the other candidates.

Pigs, dogs, and other strong performers

Two domesticated animals illustrate why the measure matters. Pigs perform well on spatial learning, object manipulation, and memory tasks in laboratory studies, and some comparisons have described pigs as outperforming dogs on problem-solving and memory measures. Dogs, by contrast, excel at social intelligence, especially reading human gestures and cues, an ability shaped by thousands of years of living alongside people. Neither species is a plausible overall winner, but each displays real cognition tuned to a different life. The same logic applies to rats, which learn mazes and multi-step tasks quickly, and to ravens, which show planning and social reasoning in corvid studies.

What Each Measure Would Crown

The table below summarizes which candidate leads on each major measure, based on the evidence discussed above. It is a summary of research emphasis, not a league table with a single champion.

Measure	Strongest evidence	What to keep in mind
Breadth across many measures	Chimpanzees	Broadest research base, so the lead partly reflects how much is known
Learned vocal labeling	Bottlenose dolphins	Signature whistles used to address specific individuals
Mirror self-recognition	Chimpanzees, dolphins, elephants, magpies (contested)	Few species pass; the test favors vision and disadvantages other senses
Tool manufacture	New Caledonian crows	Betty’s hook bending is qualified by later field research
Abstract concepts and number	African gray parrots	Strongest evidence comes mainly from one bird, Alex
Independent evolution of intelligence	Octopuses	Solitary life means less social cognition evidence
Social memory and care	Elephants	Strength lies in long-term social knowledge, not puzzles
Reading human cues	Dogs	Shaped by domestication alongside people

Read this way, the useful question becomes smartest at what, and for which kind of life.

How to Judge Smartest Animal Rankings

Because this topic attracts confident rankings, it is worth knowing how to spot weak ones. A ranking deserves skepticism when it names one winner without saying which measure was used, when it relies on a single anecdote, when it treats brain size as decisive, or when it presents contested findings as settled. A species that fails the mirror test may still show self-awareness through smell or hearing.

Stronger articles do three things. They name the measure. They attribute superlatives to studies. And they report qualifications, such as the later field research on crow tool bending, rather than hiding them. The same standard applies to claims about humans: this article focuses on nonhuman animals and does not rank humans against them. Recognizing intelligence in other species also has practical consequences for how they are treated in research, captivity, and conservation, which is one reason this research matters beyond curiosity.

The Honest Answer

So, what is the smartest animal? Among nonhuman animals, chimpanzees have the broadest evidence across the most measures, which is why researchers most often describe them as the leading candidate overall. Dolphins lead on vocal labeling, elephants on long-term social memory, and New Caledonian crows on tool manufacture. African gray parrots show abstract concepts once thought to be beyond birds, and octopuses show that a completely different brain can produce flexible problem-solving.

Any article that gives you a single name without those qualifiers is simplifying past the point of accuracy. The more accurate answer is a short list, with a measure attached to each name, and an acknowledgment that future research could change the list.

Frequently Asked Questions

What is the smartest animal in the world?

There is no settled single winner among nonhuman animals. Chimpanzees are most often described by researchers as the leading candidate overall because they perform strongly across tool use, problem-solving, social learning, and self-recognition. Dolphins, elephants, crows, parrots, and octopuses each lead on specific measures.

Is the smartest animal the chimpanzee, the dolphin, or the octopus?

Each leads on a different measure. Chimpanzees lead on breadth across measures. Bottlenose dolphins lead on learned vocal labeling through signature whistles. Octopuses lead as an example of intelligence evolving independently in an invertebrate. No single study ranks all three on the same overall scale.

How do scientists measure animal intelligence?

Scientists use tests of problem-solving, tool use and manufacture, communication, social learning, memory, and self-recognition, including the mirror test. They also consider brain organization, but brain size alone is not decisive.

Do animals know they exist?

Some animals show mirror self-recognition, which researchers treat as evidence of one form of self-awareness. Chimpanzees, bottlenose dolphins, and elephants are among the species reported to pass mirror tests under controlled conditions. Eurasian magpies were reported to pass in one early study, but a later replication did not confirm the result, so the magpie finding is contested. Failing the test does not prove an animal lacks all self-awareness, because it relies heavily on vision.

Are pigs smarter than dogs?

The answer depends on the measure. Pigs tend to perform strongly on spatial learning, object manipulation, and memory tasks, and some comparisons describe pigs as outperforming dogs on problem-solving measures. Dogs excel at social intelligence, especially reading human gestures and cues. Neither result makes one species smarter in every sense.

Are crows smarter than parrots?

Crows and parrots excel in different areas. New Caledonian crows are especially strong on tool manufacture and physical problem-solving. African gray parrots are especially strong on vocal learning, categories, and numerical concepts.

Why is brain size not a reliable measure of intelligence?

Larger animals tend to have larger brains, and much of that tissue runs a larger body. Brain organization, neuron density, and lifestyle demands matter as much as size. Birds with small brains and octopuses with a very different nervous system both outperform larger-brained animals on some tasks.

Could a less studied animal turn out to be smarter?

Yes. Rankings reflect current research, and some species have been studied far more than others. A species that looks unremarkable today might perform strongly once researchers design tests suited to its senses and lifestyle.

Sources & references

• Gallup, Gordon G. Jr. "Chimpanzees: Self-Recognition." Science, 1970. Mirror test study in which chimpanzees used mirrors to investigate dye marks on their own faces.
• Plotnik, Joshua M., de Waal, Frans B. M., and Reiss, Diana. "Self-Recognition in an Asian Elephant." Proceedings of the National Academy of Sciences, 2006. Mirror and mark test study with three female Asian elephants at the Bronx Zoo.
• Janik, Vincent M., et al. "Bottlenose Dolphins Can Use Learned Vocal Labels to Address Each Other." Proceedings of the National Academy of Sciences, 2013. Signature whistle playback study with wild bottlenose dolphins.
• Bruck, Jason N., Walmsley, Sam F., and Janik, Vincent M. "Cross-Modal Perception of Identity by Sound and Taste in Bottlenose Dolphins." Science Advances, 2022. University of St Andrews study of individual recognition across hearing and taste.
• Weir, Alex A. S., Chappell, Jackie, and Kacelnik, Alex. "Shaping of Hooks in New Caledonian Crows." Science, 2002. University of Oxford study of Betty the crow bending wire into a hook.
• Von Bayern, Auguste M. P., et al. "Compound Tool Construction by New Caledonian Crows." Scientific Reports, 2018. Max Planck Institute for Ornithology and University of Oxford study of crows combining tool parts.
• Rutz, Christian, et al. Field research on tool bending in wild New Caledonian crows, reported in Royal Society Open Science, 2016. Qualification to the interpretation of Betty's hook bending.
• Pepperberg, Irene M. Studies of numerical competence and the zero-like concept in Alex the African gray parrot. Journal of Comparative Psychology, 2005. Brandeis University research.
• Natural History Museum, London. "Octopuses Keep Surprising Us." Report on octopus arm control, including the 2011 maze experiment on central brain control of an arm.
• Boal, Jean G., Dunham, Aaron W., Williams, Katherine T., and Hanlon, Roger T. Experimental evidence for spatial learning in octopuses (Octopus bimaculoides). Journal of Comparative Psychology, 2000.