Animal intelligence is difficult to determine because "intelligence" comes in different forms. Examples of intelligence types include language understanding, self-recognition, cooperation, altruism, problem solving, and mathematical skills. It's easy to identify the intelligence of other primates, but there are many other species that may be smarter than you think. Here are some of the cleverest.

Main points

• Both vertebrates and invertebrates possess high intelligence.

• Testing the intelligence of non-human animals is difficult. The Mirror Test is a measure of self-awareness. Social skills, emotional abilities, problem solving, and mathematical abilities also indicate intelligence.

• All vertebrates exhibit some degree of intelligence. Vertebrates include mammals, birds, reptiles, amphibians, and fish. Cephalopod and insect groups possess high levels of invertebrate intelligence.

  

  
  

  
  

1. Crows and crows

The entire corvid family of birds is intelligent. This group includes magpies, jays, crows and crows. These birds are the only non-primate vertebrates to invent their own tools. Crows can recognize human faces, communicate complex concepts with other crows, and think about the future. Many experts compare the intelligence of crows to that of a 7-year-old human child.

2. Chimpanzee

Chimpanzees are our relatives in the animal kingdom, so it's no surprise that they display similar intelligence to humans. Chimpanzees make spears and other tools, display a wide range of emotions, and recognize themselves in mirrors. Chimpanzees can learn sign language to communicate with humans.

3. Elephant

Elephants have the largest brains of any land animal. The elephant's cerebral cortex has as many neurons as the human brain. Elephants have extraordinary memories, cooperate with each other, and display self-awareness. Like primates and birds, they play.

4. Gorilla

Like humans and chimpanzees, gorillas are primates. The gorilla named Koko is known for learning sign language and caring for pet cats. Gorillas can form primitive sentences to communicate with humans and understand the use of symbols to represent objects and more complex concepts.

5. Dolphin

Dolphins and whales are at least as smart as birds and primates. Like primates, dolphins and whales are mammals. Dolphins have large brains relative to their body size. The human brain has a very complex cortex, but a dolphin's brain has even more folds! Dolphins and their relatives are the only marine animals to pass the mirror test of self-awareness.

6. Pig

Pigs can solve mazes, understand and express emotions, and understand symbolic language. Piglets grasp the concept of reflection at a younger age than humans. Six-week-old piglets can figure out where food is when they see it in a mirror. By comparison, it takes human babies several months to understand reflexes. Pigs also understand abstract representations and can use this skill to play video games using joysticks.

7. Octopus

Although we are most familiar with the intelligence of other vertebrates, some invertebrates are extremely intelligent. The octopus has the largest brain of any invertebrate, but three-fifths of its neurons are actually in its arms. Octopuses are the only invertebrates that use tools. An octopus named Otto has been known to throw rocks and spray water at bright overhead lights in aquariums to short-circuit them.

8. Parrot

Parrots are thought to be as intelligent as human children. The birds solved puzzles and understood the concept of cause and effect. The Einstein of the parrot world is the African gray parrot, a bird known for its amazing memory and counting abilities. African gray parrots can learn a large number of human words and use them in context to communicate with people.

9. Puppy

Man's best friend uses his intelligence to connect with humans. Dogs understand emotions, show empathy and understand symbolic language. According to canine intelligence expert Stanley Coren, the average dog understands about 165 human words. However, they can learn more. A border collie named Chaser demonstrated the ability to understand 1,022 words. An analysis of his vocabulary was published in the February 2011 issue of the Journal of Behavioral Processes.

10. Raccoon

Aesop's fable "The Crow and the Pitcher" may be about a raccoon. Researchers from the USDA's National Wildlife Center and the University of Wyoming gave raccoons a jug of water filled with marshmallows and some pebbles. To reach the marshmallow, the raccoon must raise the water level. Half the raccoons know how to use pebbles to get food. Another simply found a way to knock down pitchers.

Raccoons are also very good at picking locks and can remember the solution to a problem for three years.

11. Other smart animals

In fact, this list of ten animals only scratches the surface of animal intelligence. Other animals with super intelligence include mice, squirrels, cats, otters, pigeons, and even chickens.

Colony-forming species such as bees and ants exhibit varying intelligences. While individuals may not be able to accomplish great feats, insects collectively solve problems in a way that rivals vertebrate intelligence.

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