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NOVA

自然 · 历史
S41 E20 Why Sharks Attack
本集简介

In recent years, an unusual spate of deadly shark attacks has gripped Australia, resulting in five deaths in ten months. At the same time, great white sharks have begun appearing in growing numbers off the beaches of Cape Cod, Massachusetts, not far from the waters where Steven Spielberg filmed the ultimate shark fright film, Jaws. What's behind the mysterious arrival of this apex predator in an area where they've rarely been seen for hundreds of years? Are deadly encounters with tourists inevitable? To separate fact from fear, NOVA teams up with leading shark experts in Australia and the United States to discover the science behind the great white's hunting instincts. Do sharks ever target humans, or is each attack a tragic case of mistaken identity? And can a deeper understanding of shark senses lead scientists to design effective deterrents and help prevent future attacks?

上一集
2014/04/23 S41 E19 8
Inside Animal Minds: Who's the Smartest?

What would it be like to go inside the mind of an animal? Now, the revolutionary science of animal cognition is revealing hard evidence about how animals understand the world around them, uncovering their remarkable problem-solving abilities, and exploring the complexity of their powers of communication and even their emotions. In the three-hour special "Inside Animal Minds," NOVA explores these breakthroughs through three iconic creatures: dogs, birds, and dolphins. We'll travel into the spectacularly nuanced noses of dogs and wolves and ask whether their reliance on different senses has shaped their evolution. We'll see through the eyes of a starling in flight and test the tool-using skills of one of the smartest birds, the crow. We'll listen in as scientists track dolphins in the Caribbean and elephants on the African savannah, trying to unlock the secrets of animal communication. As we discover how researchers are pushing the animal mind to its limits, we'll uncover surprising similarities to—and differences from—the human mind.

What makes an animal smart? What forces of evolution drive brains to become more complex? Many scientists believe the secret lies in our relationships. Throughout the animal kingdom, some of the cleverest creatures—including humans—seem to live in complex social groups, like dolphins, elephants, and apes. Could the skills required to keep track of friend and foe make animals smarter? To find out, NOVA goes inside the social lives of some of the smartest animals on the planet. Off the coast of Florida, we see dolphins team up to catch fish by whipping up a wall of muddy water that drives the meal right into their companions' waiting mouths. It seems that the dolphins are working together to plan their hunt. But are they really? Biologists go on a quest to decipher the secrets of animal societies, from the seas of the Caribbean to the plains of Africa. Do dolphins and elephants have "language?" Do chimps have a sense of fairness? And are any animals besides ourselves capable of feeling empathy?