Animals are far smarter than we ever realized.
If we've learned one thing from the past few decades of animal research, it's that many species have much more going on inside their brains than we previously thought. Experiments show that animals can solve puzzles, learn words, and communicate with each other in remarkably sophisticated ways.
Here are a few of the most impressive feats we've seen thus far.
1) Crows can solve puzzles as well as five-year-olds
A series of recent experiments have revealed crows' remarkably sophisticated problem-solving skills.
In one study conducted at the University of Auckland, researchers found that when presented with tubes of water that contained a floating treat, crows figured out that dropping other objects into the tubes would cause the water level to rise, making the treat accessible. They also figured out that they could get the treats fastest if they chose tubes with higher water levels to start, and if they dropped objects that sank, rather than ones that floated.
Other research, meanwhile, has shown that crows can intentionally bend a piece of wire in order to fish a treat out of a narrow tube. On the whole, researchers put their problem-solving skills roughly on par with those of 5 to 7 year-old children.
2) Dolphins call each other by unique names
Dolphins are remarkably intelligent in all sorts of ways. In captivity, they can be quickly trained to complete tasks for treats and are known to mimic human behavior solely for the fun of it. In the wild, they're been observed putting sponges over their snouts to protect themselves from spiny fish while hunting, and killing spiny fish so they can use their spines to extract eels from crevices.
But one of the most striking examples of how smart they are is the fact that each dolphin seems to have a characteristic whistle that represents itself. In other words, a dolphin's whistle seems to be much like its name.
In experiments, dolphins will swim towards a speaker emitting the whistle of a family member much more often than an unknown dolphin's, and when a mother dolphin is separated from her calf, she'll emit the calve's whistle until they're reunited. Most recently, researchers found that dolphins behave differently upon hearing the whistle of a dolphin they'd last seen 20 years earlier, compared to a stranger's — they're much more likely to approach the speaker and whistle at it repeatedly, trying to get it to whistle back.
3) Elephants can cooperate and show empathy
For years, researchers in the field have observed elephants cooperating in sophisticated ways. Families of related elephants travel together in clans, communicating via low-frequency rumbles. At times, they'll form circles around calves to protect them from predators, or carry out coordinated kidnappings of calves from competing clans in shows of dominance.
More recently, the same levels of coordination have been observed in controlled experiments. In one, pairs of elephants quickly learned to pull on a rope at the same time to get a treat — and not to pull alone, as that would have ruined the chance of getting it.
Other work seems to suggest that elephants can show genuine empathy.
In general, animals show little interest in dead members of their species — typically, they briefly sniff them before walking away or eating them. Elephants, however, show a special interest in elephant remains, lingering near them and in some cases becoming agitated around them. One study quantified this behavior: when shown an elephant skull, African elephants spent twice as long looking at it as buffalo or rhino skulls, and they investigated sticks of ivory for six times as long as pieces of wood.
Finally, field researchers have observed elephants consoling each other — something seldom seen in other species. Typically, when an elephant becomes perturbed, it'll make squeaking noises and perk its ears up. Frequently, other elephants from the same clan will come and stroke its head with their trunks, or put their trunk in its mouth.
4) Dogs can learn hundreds of words
There are many different examples of canine intelligence, but one of the most remarkable is a border collie named Chaser. A psychology researcher named John Pilley has trained Chaser to recognize the names of 1,022 different toys. When Pilley names a specific toy, Chaser is able to retrieve the correct one more than 95 percent of the time.
Recently, Pilley taught Chaser verbs, in addition to nouns: she can follow instructions to pick a toy up, put her nose on it, or put her paw on it. All this took countless hours of training — and all dogs might not be capable of it — but it's still a remarkable achievement of canine intelligence.
5) Chimps are crazy good at memory puzzles
It may not be a huge surprise that chimps are smart, given that they're our closest relatives. But the degree of their intelligence — and, in some areas, the way it rivals human intelligence — is remarkable.
A chimp named Ayumu who lives at a research institute in Kyoto, Japan, for instance, has become world-famous for his performance on a speed and memory-based game. As part of the game, 9 numbers are shown are shown in particular spots on a screen for a fraction of a second, and the player must remember their location and reproduce it afterward. You can play a simplified version of the game here.
Ayumu is not only capable of playing this game, but is better than any human who's challenged him so far. When the numbers are shown for an extremely short amount of time (as little as 60 milliseconds), Ayumu is significantly more accurate than people, including college students and memory champions.
Scientists still don't entirely understand how he's so good, but they hypothesize he's doing something called subitizing — looking at a number of objects and immediately taking them in without sequentially counting them. Most humans can do this for up to four items, but Ayumu may be capable of doing it for many more.
6) Cockatoos can pick locks
Cockatoos, like crows, can solve difficult puzzles in order to get treats. And a 2013 study showed just how complex these puzzles can be: they required the birds to open a box (which contained a cashew) by removing a pin, unscrewing a screw, pulling out a bolt, turning a wheel, and finally sliding out a latch.
Obviously, this takes a long time for an animal that doesn't have opposable thumbs. But one cockatoo worked at it for a full two hours, ultimately solving the puzzle and showing that the birds are capable of striving towards goals that are much more distant than the researchers had previously thought.
Other birds in the experiment, meanwhile, learned from the first bird and completed the whole puzzle much more quickly. And when the puzzle was altered so that the five steps had to be completed in a different order, the birds seemed to understand this, and attacked it accordingly instead of trying to replicate the previous solution.
7) Octopuses are weirdly intelligent in ways we don't understand
Octopus intelligence is tough to study for a few reasons: they're aquatic, difficult to keep alive in captivity, and most live relatively deep in the ocean. Most importantly, octopuses inhabit an environment dramatically different than ours — so it stands to reason that their intelligence is directed at solving very different goals.
But some scientists believe that they're smart in ways that are qualitatively different from us and the other species on this list. One reason is that they have the largest brains of any invertebrate — but though they actually have more neurons than humans, sixty percent of these cells are in their arms, not their brains. As a result, their arms seem to be individually intelligent: when cut off, they can crawl away, grab food items, and lift them up to where the octopus' mouth would be if they were still connected.
Meanwhile, octopuses seem to have a keen sense of aesthetics, even though they're likely colorblind. Field researchers have observed octopuses collect rocks of a specific color to camouflage their den, and many species can change color to blend in with their environment. The way they accomplish this, it's hypothesized, is that they actually sense color with their skin itself and respond accordingly.