Humans have the ability to learn, to reason and solve problems. We’re self-aware, and we’re also conscious of the presence, thoughts and feelings of others. We make tools and practice the art of deception. We’re creative. We think abstractly. We have language and use it to express complex ideas. All of these are arguably signs of intelligence. Scientists may not agree on the best and fullest definition of intelligence — but they generally agree that humans are highly intelligent.
Other members of the animal kingdom exhibit signs of intelligence as well, and some scientists might say the definition of animal vs. human intelligence is merely a matter of degree – a point that was brought home in 2005 when the London Zoo put “Homo sapiens” on display in the exhibit pictured here. Click ahead to learn about nine other species that stand out for their smarts.
Chimps are almost like us
Tetsuro Matsuzawa / AP
If we humans possess intelligence, chimpanzees must have some as well: Our genomes are at least 98 percent identical. Chimps make and use tools, hunt in organized groups and engage in acts of violence. Wild troops have distinct behaviors and customs. Field observations and lab experiments show chimps are capable of empathy, altruism and self-awareness. In the experiment pictured here, chimps performed better than humans on a number memory test.
Elephants exhibit self-awareness
The sheer size of their brains suggests that elephants must know a thing or two about the ways of the world. They have been seen consoling family members, helping other species in times of need, playing in water and communicating with one another via vibrations sensed in their feet. A crowning achievement, some researchers say, was when this female Asian elephant named Happy recognized herself in the mirror. The complex behavior is shared only with humans, great apes and dolphins.
Cephalopods have big brains
Are octopi, squids and cuttlefish smart? That’s a matter of scientific intrigue, but such cephalopods are certainly among the brainiest invertebrates in the sea. The cephalopod brain surrounds the esophagus, but shares with the human brain features of complexity such as folded lobes and distinct regions for processing visual and tactile information. The how-smart debate swirls around deciphering observations that the creatures have a seemingly irrepressible curiosity, a disdain for boredom, an ability to learn and the capacity to use tools. The octopus pictured here exerts precise muscle control to eat.
Squirrels can be deceptive
Gabriel Bouys / AFP – Getty Images file
Is the squirrel pictured here plotting deception? Perhaps. Researchers recently reported that the rodents put on elaborate shows of deceptive caching to thwart would-be thieves. The behavior increased in a lab experiment after squirrels observed humans stealing their peanuts. The researchers called the finding a sign that squirrels can interpret intentions of others, though it could just be a case of learned behavior. Other studies have shown the critters make three-dimensional maps to recall where they cache their nuts. And squirrels in California will cover their fur in the scent of rattlesnakes to mask their own scent from predators.
Man’s best friend
University of Vienna
Are dogs intelligent or just really good at basic obedience? They can learn to sit, lie down and fetch, for example, but can they read their owner’s intentions? Research suggests they can at least find food in response to non-verbal cues, a type of understanding that scientists think may be akin to the human ability to understand someone else’s point of view. The dog in the experiment pictured here accurately discriminated between photos of dogs and photos of landscapes — an indication the dog was able to form the concept of “dog.”
Pigs are wise … and clean
Paulo Whitaker / Reuters
Here’s the dirt on pigs: They are perhaps the smartest, cleanest domestic animals known – more so than cats and dogs, according to some experts. But pigs don’t have sweat glands, so they roll around in the mud to stay cool. A sign of their cleverness came from experiments in the 1990s. Pigs were trained to move a cursor on a video screen with their snouts and used the cursor to distinguish between scribbles they knew and those they were seeing for the first time. They learned the task as quickly as chimpanzees.