Who Are the Smartest Animals on Earth?

As the scientific community continues making strides in the field of animal intelligence, one theme seems to keep emerging: that animals are smarter than we expect.

Who are the smartest animals in the world?

African Gray Parrots

Best known for their ability to repeat words and phrases after only hearing them once or twice, these birds' intelligence goes much deeper than simple mimicry. In a 2019 study, researchers gave an African Gray Parrot a classic test often used to measure logic and reasoning in young humans. The parrot was presented with two cups; one contained a hidden treat, the other was empty. When shown which cup was empty, the parrot correctly inferred that the reward must be beneath the lid of the other cup. Humans don't develop this ability to make "inferences through exclusion" until they're about two-and-a-half years old. However, the parrot's test went even further. The researchers incorporated more cups to make the logical games even more complicated, and the parrot continued to choose the correct cups, sometimes even "gambling" in hopes of finding his favorite treat (a single Skittle) over a less enticing nut. Throughout these tests, the African Gray Parrot performed better than most five-year-old humans do.

Bees

You might have heard in recent years about how important bees are to the planet's ecosystems. But bees aren't just hard workers—they're smart, too! There's evidence that bees are sentient beings, with the abilities to feel emotions and imagine abstract ideas. In a new book titled The Mind of a Bee, ecologist Lars Chittka details his findings observing female worker bees. Through a series of experiments, Chittka found that some "genius bees" learned tasks faster than others and taught the rest of the colony through example. He also found that the bees could feel an object in the dark and figure out what it looks like using their imaginations, and that they had clear emotional responses to negative and positive stimuli.

Bottlenose Dolphins

For years, dolphins have been heralded as the smartest animals on Earth, second only to humans—though some would even contest that ranking. Aside from humans, dolphins have the greatest brain-to-body ratio among animal species, including primates. But dolphin's brains aren't just large in size— researchers have found that dolphins' minds are miraculously complex. They contain brain cells called "spindle neurons" that give dolphins the ability to recognize themselves in a mirror, hold onto memories, solve problems, utilize languages, and adapt to changes. The region of a dolphin's brain responsible for processing complex emotions—known as the "limbic system"—appears to be even more intricate than it is in humans, according to neuroscientist Lori Marino.

Chimpanzees

Chimps are our closest living relatives. Considering we share about 99 percent of the same DNA with these great apes, it’s not too surprising to learn that chimpanzees are highly social creatures who hunt cooperatively, communicate their emotions, and develop cultures that are unique from one community to the next. What might surprise you is that, not very long ago, we once knew next to nothing about the impressively intelligent chimp. That all changed when the famous anthropologist Jane Goodall became the first scientist to observe a chimp in the wild using a stick as a tool to catch and eat termites. Before that discovery, many believed that the ability to create tools was a distinctly human attribute.

Crocodiles

Crocodiles are dangerous predators, mostly nocturnal, and spend most of their time in murky, overgrown swamps. So it has not been easy for scientists to observe them, or their relatives like the American Alligator, in the wild. However, research over the past several years has shown that crocodiles are exceptional hunters, and not just because they have the strongest biting power in the animal kingdom. Crocodiles often work in groups to surround, lure, and ambush their prey. According to a 2014 research paper from the University of Tennessee, crocodiles are—in a sense—assigned different roles based on their size and ability, putting them into a "very select club of hunters... capable of coordinating their actions in sophisticated ways and assuming different roles according to each individual's abilities."

Crows

Historically and culturally depicted as a sign of bad luck, crows should be more accurately known as one of the savviest creatures to soar the skies. Crows can remember a human face for years, even teaching their offspring about humans to be wary of. They also communicate with regional dialects and have been observed using tools. Perhaps most significantly, however, in 2021 scientists made the breakthrough discovery that crows are able to have unique, subjective experiences—so two crows may witness the "same event" but perceive and process the experience differently. Until recently, this level of consciousness was incorrectly thought to be a purely human trait.

Elephants

You may have heard the phrase "an elephant never forgets." It's not just an expression. There are various scientific accounts displaying the powerful recall that elephants possess. For example, in 1999 when two old elephant pals were reunited at a sanctuary in Tennessee, the pair became so excited to see each other that they could hardly contain their euphoria, according to the sanctuary's founder Carol Buckley. She later did some digging to find out how the two females—named Shirley and Jenny—knew each other. She found out that they had crossed paths in the circus, some 23 years earlier. Elephants are also insightful problem solvers, as evidenced by a study about 10 years ago in which a male elephant used trial and error to manipulate his surroundings so that he could reach previously inaccessible food (yet another animal observed using tools!).

Killer Whales

Weighing in at 15 pounds, the brain of a killer whale is the second largest of all marine mammals, behind only the sperm whale. But did you know that orcas (also known as killer whales) are actually not whales at all, but dolphins? One explanation for this misconception is that, long ago, sailors who observed orcas deftly hunting and eating whales gave them the nickname, "killer of whales," but over time the "of" got lost. Much like other big-brained mammals, the orca has captured the fascination of biologists, who have found that each family, or "pod," seem to have developed their own unique set of behaviors—especially differing hunting techniques—that have been passed down through generations. Orcas, like humans and the great apes, are cultural creatures.

Octopuses

Octopus intelligence is so impressive that it is not just centralized in one place, but throughout their entire body. Like us, octopuses have a brain that acts as the headquarters of the nervous system. However, octopuses also have a "mini brain" located in each one of their tentacles, giving them a total of nine brains altogether. These smaller brains allow each arm to move, touch, and taste independently from the others. Putting their multiple minds and many neurons to good use, octopuses are constantly teaching us not to underestimate invertebrates. Researchers have found that octopuses are skilled at problem solving, figuring out puzzles, and finding their way out of difficult predicaments. They've even been observed using tools, first in 2009 when researchers found veiny octopuses in Indonesia stockpiling open coconut shells for later use as a sort of body armor.

Orangutans

These shaggy-haired apes are like other primates in that they've been observed using tools, developing cultures, and using unique dialects. In 2018, though, humans discovered a new layer of orangutan intelligence once thought to be only possessed by humans. After orangutan mothers spotted what they thought to be potential predators (which were actually just scientists draped in tiger-striped sheets), the mothers waited about seven minutes and then alerted their young to the threat through a series of shouts. This ability to "discuss" objects and events from the past, that are no longer within view, is known as "displaced reference," and appears to be yet another fallen pillar once believed to separate humans from animals.

Pigs

Despite historically being exploited as primarily a source of food, pigs have proven themselves to be smart, emotional, and social animals deserving of far more respect than they've been given. Countless experiments and studies have found that pigs can be trained to complete surprisingly involved tasks—like playing video games. They are able to remember important pieces of information that inform their decisions. They also thrive on social hierarchy, with the ability to feel empathetic toward others in their community. Because pigs are so emotional and social, researchers say that it's all the more important for a pig to be raised in a happy, stimulating environment, rather than one full of boredom and suffering.

Rats

There are probably few animals whose brains have been studied more consistently than the rat, on whom researchers have conducted countless psychological experiments aimed at better understanding our own minds. This is because, even though it's much smaller, the rat's brain is surprisingly similar to a human's in terms of makeup and function. While rats do not appear to have thought processes as complicated as other animals', they can figure things out and apply learned information with remarkable speed, sometimes even more quickly than humans can at the same tasks.

Ravens

Like crows and other relatives in the corvid family, ravens are known as crafty and clever birds. In 2020, a group of researchers set out to comprehensively measure just how smart ravens really are through a slate of tests that have been used in the past to study children, apes, dogs, and monkeys. The results showed that by just four months of age, the young ravens had successfully mastered most of the tasks they were challenged with. According to the publication in Scientific Reports, the ravens proved themselves to be on par with primates and human toddlers who had been given similar tests.

How do animals demonstrate intelligence?

Attention

Central to the way animals learn and interact, attention refers to an animal's ability to filter information from a range of stimuli.

Cognitive Bias

Cognitive bias refers to errors the mind makes when quickly processing the world surrounding it. In animal psychology, researchers have found that animals raised in an unhappy environment are biased toward interpreting the world in a pessimistic way, while animals raised in a happy environment are more predisposed to interpret things optimistically.

Consciousness

Your awareness of yourself—your thoughts, memories, and feelings—all fit under the umbrella term of consciousness. Once thought to be an attribute unique to humans, modern breakthroughs have redefined consciousness as something shared throughout much of the animal kingdom.

Insight

Defined as the ability to discern a solution through means which are not obvious, animals display insight when they find a way around a problem through a series of trial and error, like the seven-year elephant named Kandula. After several days of failed attempts during a study, Kandula realized he could move objects around him in such a way that he could finally reach previously inaccessible food.

Language

Defined as a system for communicating information through auditory behaviors, specific body movements, or written symbols, language is not unique to humans. Whether it's the pulses and clicks used by dolphins, shrieks from great apes, or non-verbal gestures often seen in dogs and pigs, many animals have unique ways of communicating their thoughts and feelings.

Memory

Memory is the ability to retain information or past experiences across some interval of time. Animals use memory to remember faces, avoid potential threats, and make smarter decisions about their future.

Numeracy

Most human children are able to count to 10 by around the age of four. Other animals, however, have also displayed a basic ability to work with numbers. Baby chicks, for example, have successfully shown an understanding of simple arithmetic in studies involving food rewards, making calculations like "three treats plus one treat equals four treats."

Perception

Simply put, perception refers to our awareness of our environment through sensations. It's long been accepted that all mammals have perception. However, recent strides have been made in showing that other creatures like insects and crustaceans perceive their environments, and that they can therefore suffer.

Reasoning And Problem Solving

When faced with difficult situations, many animals will use reasoning and problem solving to get the solution. Crows are some of the animal kingdom's cleverest problem solvers. When researchers presented a crow with food submerged in water too deep to reach, she dropped solid objects into the water. This raised the water level, bringing food closer to the surface for her to grab.

Sapience

Often defined simply as "wisdom," this attribute in animals refers to the ability to behave with judgment. Many animal species develop unique cultures in which older members share wisdom with the younger ones. The culturally-minded whales, dolphins, primates, and corvids are some particularly sapient animals.

Spatial Cognition

The ability to understand where we are in relation to the world around us—defined as spatial cognition—is a fundamental building block for humans' physical and mental experience, and an essential part of survival for every creature in the animal kingdom.

Theory Of Mind

In order to have successful social interactions, it's vitally important for humans to understand that others have beliefs, desires, and mental states different from our own. The ability to attribute mental states to ourselves and others is known as the Theory of Mind. Whether or not animals possess this attribute is still a topic of scientific debate, though evidence that they do seems to be growing.

Time perception

Species perceive time at varying speeds. According to a study in 2014, smaller animals with faster metabolisms tend to take in more information than a larger animal would. In other words, smaller animals experience the world in slow motion, compared to how we see it.

Tool And Weapon Use

Ever since Jane Goodall made the landmark discovery of a chimpanzee using a stick as a device to catch termites in the 1960s, many more animals have been observed fashioning tools and weapons out of objects around them. Octopuses, birds, pigs, and dolphins are just some of the animals who have joined the club as toolmakers.

Current Research On Animal Intelligence

How Animal Intelligence Is Measured

Just as there are many different types of animal intelligence, there are many ways to measure it. Some scientists evaluate animals' cognitive reasoning and problem-solving skills through games, tests, and puzzles—such as the classic laboratory rat running through a maze, or the popular method of hiding treats inside of cups.

Other scientists utilize modern technology to look closely at the inner workings of an animal's brain. In 2018, Dr. Gregory Berns, a neuroscientist at Emory University, performed MRI scans of dogs to get a better idea of how the different regions of their brains reacted to different stimuli. Dr. Berns wanted answers to questions like, for example, whether the reward center in a dog's brain would light up upon seeing a picture of her favorite toy, the same way it would when seeing the physical toy itself.

A less technologically involved test, known as the mirror test, is used to determine whether an animal has self-awareness. Researchers will put a disfiguring mark somewhere around the animal's forehead and place him in front of a mirror. If the animal attempts to touch or remove this mark upon seeing himself in the mirror, he has "passed the test" and demonstrated a level of self-awareness.

It's important to keep in mind, however, that no test is sufficient in comprehensively determining just how smart an animal is. Many tests can only produce narrow results, and if an animal "fails" an intelligence test, it does not necessarily mean that the animal lacks that sort of intelligence. It could simply mean the researchers failed to set up the test in a way that measures the animal's abilities accurately.

Animal Intelligence Compared To Humans

Since there is no uniform standard for evaluating intelligence across species, there is no easy way to accurately compare animals' intelligence to humans'. It's a bit like the old saying about judging a goldfish based on her ability to climb a tree. Different animals simply have different strong suits.

For example, here are areas in which rats' brains appear to work faster than humans'. In terms of hunting, most humans would have a far lower success rate than experts like killer whales or crocodiles. The standard domestic dog can do better on some self-control tests than chimps, yet chimps are widely considered to be far more intelligent than dogs.

What appears to be more important than comparing who is "smarter" than whom, is studying the types of skill sets different animals acquire and how their environment shapes these strengths and weaknesses.

The Smart Way to Eat

Animal psychologists and scientists have made great strides in recent years that help us better understand the minds of all kinds of animals. The main takeaway is that the creatures we share the planet with are far more intelligent, emotional, and aware than we once thought.

That goes for animals like cows, pigs, and chickens who suffer cruel and inhumane conditions on factory farms every single day. Fortunately, by switching to a plant-based diet and leaving animal products off your plate, you can ensure that you don't support this kind of animal cruelty. The Humane League can help you get started. Get your free plant-based eating starter kit and be the change for animals today.