We humans tend to think we're pretty smart. We've got descriptive language. We've got art and can build museums in which to showcase it. The flip side, of course, is that we've also learned to build bombs. But as we learn more about the rest of the animal world, it's becoming pretty clear that other beasts are pretty darn intelligent. Chimpanzees, bonobos and other primates and great apes get a lot of recognition for their brains, but for this list, we're looking a little farther afield in the ocean, on farms for the smartest non-primates.
As it turns out, being piggy is actually a pretty smart tactic pigs are probably the most intelligent domesticated animal on the planet. Although their raw intelligence is most likely commensurate with a dog or cat, their problem-solving abilities top those of felines and canine pals.
One study showed that domestic pigs can quickly learn how mirrors work and will use their understanding of reflected images to scope out their surroundings for food. The researchers cannot yet say whether the animals realize that the eyes in the mirror are their own, or whether pigs might rank with apes, dolphins and other species that have passed the famed mirror self-recognition test thought to be a marker of self-awareness and advanced intelligence.
In a 1990s experiment, 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.
If pigs are the most intelligent of the domesticated species, octopuses take the cake for invertebrates. Experiments in maze and problem-solving have shown that they have both short-term and long-term memory. Octopuses can open jars, squeeze through tiny openings, and hop from cage to cage for a snack. They can also be trained to distinguish between different shapes and patterns. In a kind of play-like activity one of the hallmarks of higher intelligence species octopuses have been observed repeatedly releasing bottles or toys into a circular current in their aquariums and then catching them.
The octopus is the only invertebrate which has been shown to use tools. At least four specimens have been witnessed retrieving discarded coconut shells, manipulating them, and then reassembling them to use as shelter.
In many branches of mythology, the crow plays a shrewd trickster, and in the real world, crows are proving to be quite a clever species. Crows have been found to engage in feats such as tool use, the ability to hide and store food from season to season, episodic-like memory, and the ability to use personal experience to predict future conditions.
One species, the New Caledonian Crow, has been witnessed using knife-like tools cut from stiff leaves, and it will drop tough nuts onto streets busy with cars to smash them open. Crows in Queensland, Australia, have even learned how to safely eat a species of toxic cane toad. They flip the frog on its back and stab its throat, where its poisonous skin is the thinnest, in order to munch on the non-toxic innards.
Recent research suggests that crows have the ability to recognize one individual human from another by facial features, and that they can remember human faces for years. So be careful when you cross a crow.
Dolphins are among the smartest of the animal kingdom, partly because they live such social lives. They're also thought to have a sophisticated "language," though humans have only begun to unravel it. Dolphins use tools in their natural environment and can learn an impressive array of behavioral commands from human trainers. Like many of the most intelligent animals on Earth, female dolphins remain with their young for several years, teaching them all the tricks of the dolphin trade. Recent tests show that dolphins understand numbers of things, and they have displayed self-recognition a feat reserved for animals of the highest smarts.
As of 2005, scientists have observed groups of bottlenose dolphins around the Pacific Ocean using a basic tool. When searching for food on the sea floor, many of these dolphins were seen tearing off pieces of sea sponge and wrapping them around their "bottle nose" to prevent abrasions.
Elephants top our list of the wisest non-primates. They live in close-knit societies with an intricate social hierarchy. Elephants also exhibit altruism toward other animals, and pregnant females have learned how to eat particular leaves to induce labor.
They can also use tools and quickly adapt to new situations elephants have also been known to drop very large rocks onto an electric fence either to ruin the fence or to cut off the electricity. A 2010 experiment revealed that in order to reach food, "elephants can learn to coordinate with a partner in a task requiring two individuals to simultaneously pull two ends of the same rope to obtain a reward", putting them on an equal footing with chimpanzees in terms of their level of cooperative skills.
But what really sets elephants apart is their complex death rituals; other than elephants, humans and Neanderthals are the only animals known to pay respects to the dead. Often, elephants will gently investigate the bones of the newly deceased with their trunks and feet while staying very quiet. Sometimes elephants that are completely unrelated to the deceased will still visit their graves.
In the recent study, the elephants even figured out ways that the researchers hadn't previously considered to obtain food rewards. Outsmarting the humans? Not just for the apes anymore.