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Jaws is ready for your close-up

发布时间:2019-03-06 07:15:04来源:未知点击:

SHARKS were always thought to be long-sighted, but researchers who gave them an eye test found they can focus correctly on both near and distant objects. Testing a shark’s eyesight usually involves restraining it, holding different lenses up to its eyes and watching their response. But by reflecting infrared light off the back of their eyes using a camera, Bob Hueter of Mote Marine Laboratory in Sarasota, Florida, and his colleagues have shown that free-swimming lemon sharks can focus on near and distant targets (Vision Research, vol 41, p 1885). Restraining sharks may have relaxed their eye muscles,