Top 10 Smartest Animals in the World

No. 10 in our countdown is the rat, a highly intelligent yet much-maligned animal in Western cultures. But in Chinese culture, the rat is well-regarded for its cunning and resourcefulness, and for good reason. It has successfully colonized every continent on Earth except for Antarctica. And if history is any indication, they'll be there too soon enough.

Widely used in research, the lab rat has been known to find shortcuts, loopholes and escape routes in the laboratory experiments designed by the top scientific minds of our time. In fact, highly trained rats have saved thousands of lives by detecting tuberculosis (TB) in humans and sniffing out landmines around the world.

Rats trained at a Tanzania-based nonprofit organization APOPO – which stands for "Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling," in Dutch and "Anti-Personnel Landmines Detection Product Development" in English – have detected 18,300 cases of TB and destroyed 108,736 landmines and unexploded ordnances.

It takes a rat 30 minutes to check the area of a tennis court for mines, a task that could take a human four days with a metal detector, APOPO says. And it can check 100 sputum samples for TB in under 20 minutes, while a lab technician might take up to four days using conventional tests. If that wasn't impressive enough, rats can also learn to play hide and seek.

Kudos should go to the invertebrate with the strength and skill to screw a lid off a jar! No. 9 in our list of world's smartest animals is the octopus, one of the smartest creatures in the sea. This animal is still poorly understood, but scientists are constantly discovering new and impressive abilities.

Octopi play, solve problems, navigate through mazes and have respectable short-term memories. But how is an animal that belongs to the same class as the snail capable of such clever feats? It may be that the combination of strength, agility, curiosity and a lot of brainpower sets the octopus apart from its soft-bodied brethren.

An octopus brain is proportionally as large as some mammals' brains, but it displays a high level of organization, which helps it catch its prey and avoid predators. However, its shape-shifting and camouflage abilities reveal only a fraction of this remarkable creature's brainpower. Although its nervous system includes a central brain, 3/5 of the octopus's nerves are distributed throughout its eight arms which serve as eight mini brains. Well, no wonder it's so smart.

A video captured an octopus pulling two halves of a coconut shell, which it later uses as shelter. The intelligent animal knows the shells will come in handy at a future date.

Octopuses show the same smarts when brought into science labs. Researchers confirmed that octopi could recognize individual humans despite them wearing identical uniforms. In fact, the animals behaved differently around the person who fed them and the person who touched them with a bristly stick – something we humans would definitely do.

Pigeons are abundant in most major cities of North America, and many people think of them as mere pests. However, this ubiquitous bird is actually quite smart. Because pigeons have been the subjects of countless scientific experiments, there is a wealth of knowledge about their intellectual abilities.

For example, pigeons can recognize hundreds of images even after several years have passed. They can also identify themselves in a mirror, be taught to perform a sequence of movements and to discriminate between two paintings – pretty impressive for a common bird.

But that's just scratching the surface. There's a reason pigeons were used by governments and militaries around the world. Before technology progressed, these pigeons carried critical messages back and forth behind enemy lines during both World Wars. And other pigeons, equipped with tiny cameras, flew over enemy territories to gather information.

So, don't be fooled by your neighborhood pigeon pecking at the ground – this animal doesn't have a bird brain; it's a brainy bird.

This animal's dogged persistence and impeccable memory have made it the nemesis of gardeners everywhere. Most squirrels display an impressive array of tricks and strategies that help them survive, which researchers believe shows an advanced level of cunning and intellect. For starters, these intelligent creatures are essentially woodland animals that have adapted to living alongside humans, eating out of bird-feeders, flower gardens and whatever food might be lying around.

If you're a fan of the "Ice Age" films, you know how important an acorn is for Scrat, the saber tooth squirrel. Well, it's no different in real life. So much so that Eastern gray squirrels dig holes, pretend to hide their food in them and run off to other secret places to stash their food. This is known as deceptive caching, and they do this to confuse potential thieves.

Tree squirrels on the other hand, use a technique called "spatial chunking" to sort their nut pile by size, type, and perhaps nutritional value and taste. This helps them find what they want when they get hungry. They are also able to store and cache food for leaner times, and then find their hidden morsels many months later.

Despite a reputation for gluttony and poor hygiene, pigs are actually highly intelligent animals. Both domestic and wild species are known for their ability to adapt to a variety of different ecological conditions. Unlike most other ungulates, which are strictly herbivorous, pigs and their relatives are omnivores with a diet that sometimes includes worms and bugs.

Wherever they have been introduced around the world, pigs tend to out-compete the native species. Though devastating to the native species, this trend is yet another strong indication of pig cleverness.

In fact, young piglets can learn to use mirrors to find the path to a hidden food bowl. When researchers placed the food bowl behind a solid barrier, which was only visible in the mirror, seven out of the eight pigs found their food. Not only were they able to solve the concept of reflection within five hours, but pigs can also understand instructions given to them by humans.

There's a reason certain domestic pigs have become a favorite pet in the U.S. — pigs are as trainable as cats and dogs.

Crossing the street against traffic may be called "jay-walking," but jays and other members of the crow family understand better than some humans the importance of waiting for the light to change. Crows living in urban areas in Japan have been observed gathering nuts from trees and then placing them in the street for passing cars to crack open the shells. Then, after waiting patiently for the light to change, they return to the street to retrieve their nutty snack — an impressive example of animal innovation.

Crows have demonstrated abilities to create tools (like bending a piece of wire to create a hook to snag meat), identify people and animals who might pose threat and understand analogies. One study even compared their reasoning power to that of 7-year-old human children. Crows also communicate in elaborate, population-specific dialects and play games and tricks on one another.

The first thing you notice when you see an elephant is their enormous size. But contrary to popular perception, elephants are more than just lumbering giants with big ears. In fact, elephants are quite elegant, cultured, curious and have good memories. So much so, they can recognize up to 30 relatives from their urine scents – proving useful for elephants to keep track of one another.

They have been known to clean their food and use tools in various ways in the wild, and they can also follow human commands in captivity. Elephants are also extremely caring and empathetic to other members of their group and to other species, which is considered a highly advanced form of intelligence.

Elephants have the largest brain among land animals – three times larger than the human brain – weighing a hefty 10.5 pounds (4.7 kilograms) for an adult. Its brain contains 257 billion neurons, which is also three times more than the average human brain. Elephants can recognize themselves in mirrors and show signs of grief over their dead relatives.

The great apes are considered the smartest creatures after humans. Of course, humans are biased in this regard, but the intellectual capacity of the great apes is difficult to deny. After all, we share over 96 percent of the same DNA. Orangutans stand out as being especially gifted in the brains department. In fact, they can weigh costs and benefits when exchanging goods, similar to humans.

Orangutans have a strong culture and system of communication and many have been observed using tools in the wild. In one study, adult orangutans performed better than human children at making and using tools.

These intelligent animals live in widely scattered communities and form strong social bonds, which may be the key to their advanced cognitive skills. Females remain with their young for many years, teaching them all they need to survive in the forest. Unfortunately, orangutans are critically endangered with barely 100,000 left in the world.

Have you ever wondered why dolphins and killer whales are the star attraction at most aquariums? It's because they're smarter than almost any other creatures on the planet. But you probably already knew this if you watched the films featuring Flipper and Willy.

Dolphins are also extremely social animals. Schools of dolphins can be observed in the world's oceans surfing, racing, leaping, spinning, whistling and otherwise enjoying themselves. They also have a sophisticated "language," though humans have only begun to unravel it.

Like many of the most intelligent animals on Earth, dolphin females remain with their young for several years, teaching them all the tricks of the dolphin trade. Dolphins use tools in their natural environment and can learn an impressive array of behavioral commands by human trainers. In fact, The U.S. Navy trained bottlenose dolphins to find explosive mines underwater.

A dolphin's brain is four to five times larger than expected for their body size. They can recognize themselves in a mirror and comprehend and follow instructions. They also have sonar built into their DNA.

Topping our list of smartest animals is another great primate, the chimpanzee. The impressive intellectual abilities of this animal have long fascinated humans. Chimps are able to learn sign language to communicate with humans and can remember the name sign for individuals they have not seen for several years. Similar to some of the other animals on this list, chimps can also recognize themselves in mirrors and show signs of caring and mourning.

But perhaps the most amazing feature of the chimpanzee is its ability to use symbols for objects and combine the symbols in a sequence to convey a complex idea. Such intellectual gifts are probably central to maintaining this animal's complex social groups, where they form strong bonds and observe elaborate hierarchical structure.

In the wild, chimps have been observed making spears for hunting and using tools to crack open nuts and remove termites from logs. They are capable of advanced problem-solving, and they know when they've aced a test. Ready to be amazed? Here's a video of chips outperforming humans at a memory task.

This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.