That rat hiding in your house knows exactly who you are. Scientists have discovered that rats can recognize individual humans. And the rodents are geniuses at finding workarounds and exploiting weaknesses in laboratory tests. Rats have a different kind of intelligence than some of the animals humans find more relate-able—such as chimps and dolphins—but their type of smarts has made them a huge success. Rats are an adaptable, resilient species that can live in the most extreme range of climates and conditions.
Dolphins have large brains built for self-awareness and complex emotions. They may even name each other. Scientists have heard dolphins make distinct clicks and whistles that might be individual dolphin names. Dolphins’ brains are about five times bigger than the brains of other animals their size. For humans, that figure would be seven times as large as similarly sized creatures.
Elephants have surprised researchers by figuring out test solutions that the researchers hadn’t thought of themselves. These big-brained animals live in complex social groups where teamwork is the norm. Scientists have observed elephants communicating with each other through vibrations sensed in their feet. They demonstrate empathy for family members and have even aided members of other species. Elephants can recognize themselves in mirrors, a measure of self-awareness they share with humans, chimps and dolphins.
Chimps are a lot like humans. They possess genomes that are 98 percent identical to people, and make and use tools. They are able to organize in groups, express a range of emotions and may show a violent side. They’ve actually beaten humans on a memory test of numbers. Wild chimpanzees show cultural differences between tribes. For example, some groups of chimps in Africa’s Tai National Forest prefer stone tools for cracking open nuts, while others craft their tools from wood.
Like humans, pigs live in social groups, recognizing each other as individuals. They’re quick to learn tricks, such as spinning, herding sheep, opening cages and even using joysticks to play video games. Pigs have long memories for the skills they learn and for the location of stored food. And they’re tricky. If Pig A has a secret Twinkie stash, Pig B will follow to try to root it out. But Pig A will deceive the would-be Twinkie thief about the food’s location.