It's not just man's closer primate relatives that exhibit brain power. Dolphins, dogs and elephants are teaching us a few lessons, too.
Dolphin brains involve completely different wiring from primates, especially in the neocortex, which is central to higher functions such as reasoning and conscious thought.
Dolphins are so distantly related to humans that it's been 95 million years since we had even a remotely common ancestor. Yet when it comes to intelligence, social behavior and communications, some researchers say dolphins come as close to humans as our ape and monkey cousins.
"They understand concepts like zero, abstract concepts. They do everything that chimpanzees do and bonobos can do," said Lori Marino, a neuroscientist at Emory University who specializes in dolphin research. "The fact is that they are so different from us and so much like us at the same time."
In recent years, animal researchers have found that thought processes in critters aren't a matter of how closely related they are to humans. You don't have to be a primate to be smart.
Dolphin brains look nothing like human brains, Marino said. Yet, she says, "the more you learn about them, the more you realize that they do have the capacity and characteristics that we think of when we think of a person."
These mammals recognize themselves in the mirror and have a sense of social identity. They not only know who they are, but they also have a sense of who, where and what their groups are. They interact and comprehend the health and feelings of other dolphins so fast it as if they are online with each other, Marino said.
Animal intelligence "is not a linear thing," said Duke University researcher Brian Hare, who studies bonobos, which are one of man's closest relatives, and dogs, which are not.
"Think of it like a toolbox," he said. "Some species have an amazing hammer. Some species have an amazing screwdriver."
For dogs, a primary tool is their obsessive observation of humans and ability to understand human communication, Hare said. For example, dogs follow human pointing so well that they understand it whether it's done with a hand or a foot; chimps don't, said Hare, whose upcoming book is called "The Genius of Dogs."
Then there are elephants.
They empathize, they help each other, they work together. In a classic cooperation game, in which animals only get food if two animals pull opposite ends of a rope at the same time, elephants learned to do that much quicker than chimps, said researcher Josh Plotnik, head of elephant research at the Golden Triangle Asian Elephant Foundation in Thailand.
They do even better than monkeys at empathy and rescue, said Plotnik. In the wild, he has seen elephants stop and work together to rescue another elephant that fell in a pit.
"There is something in the environment, in the evolution of this species that is unique," he says.
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