澳大利亞科學家近期研究發(fā)現(xiàn)鯊魚很可能是色盲，人們可以根據(jù)這個特點研制不會誤捕鯊魚的漁具,，以及能減少遭鯊魚攻擊的服裝,。
西澳大利亞大學與昆士蘭大學的研究人員檢測了17種澳大利亞周邊不同種類的鯊魚的視網膜，發(fā)現(xiàn)這些動物只有一種能辨識顏色的視錐細胞,。人眼有三種視錐細胞,，分別能看到藍色、綠色與紅色的光,，這樣人們就能識別不同顏色的物體,。
項目負責人內森 哈特博士稱，這項調查結果可以幫助人類改進一些防止被鯊魚襲擊的措施,，也有助于研制避免誤捕鯊魚的漁具,。 “我們的研究顯示，鯊魚在探測目標時,，如果目標與其周遭環(huán)境的對比反差較大,，就比較容易被鯊魚探測到，而不是我們傳統(tǒng)認為的,，色彩艷麗的物體對鯊魚比較顯眼,，”他進一步解釋說，“我們可以設計一些對鯊魚而言與周圍環(huán)境視覺對比不是很強烈的泳裝和沖浪用具,，以減少對它們的吸引力,。”
人類視網膜布滿了能感應光線強弱的桿狀細胞和辨識顏色的視錐細胞,。桿狀細胞在光線昏暗的環(huán)境比視錐細胞的功能發(fā)揮好，而在所有17種鯊魚身上找到最常見的就是桿狀細胞,。
科學家在其中10種鯊魚身上根本找不到視錐細胞,，而另外7種鯊魚只有一種僅對一個波段的光敏感的視錐細胞，也就是說它們只能看到一種顏色,。因此,，如果鯊魚的視網膜像研究人員所稱無法辨別不同的顏色，那它們可能就是完全的色盲,。（生物谷Bioon.com）
生物谷推薦原文出處：
Naturwissenschaften, 2011; DOI: 10.1007/s00114-010-0758-8
Microspectrophotometric evidence for cone monochromacy in sharks
Nathan Scott Hart, Susan Michelle Theiss, Blake Kristin Harahush and Shaun Patrick Collin
Abstract
Sharks are apex predators, and their evolutionary success is in part due to an impressive array of sensory systems, including vision. The eyes of sharks are well developed and function over a wide range of light levels. However, whilst close relatives of the sharks—the rays and chimaeras—are known to have the potential for colour vision, an evolutionary trait thought to provide distinct survival advantages, evidence for colour vision in sharks remains equivocal. Using single-receptor microspectrophotometry, we measured the absorbance spectra of visual pigments located in the retinal photoreceptors of 17 species of shark. We show that, while the spectral tuning of the rod (wavelength of maximum absorbance, λmax 484–518 nm) and cone (λmax 532–561 nm) visual pigments varies between species, each shark has only a single long-wavelength-sensitive cone type. This suggests that sharks may be cone monochromats and, therefore, potentially colour blind. Whilst cone monochromacy on land is rare, it may be a common strategy in the marine environment: many aquatic mammals (whales, dolphins and seals) also possess only a single, green-sensitive cone type. It appears that both sharks and marine mammals may have arrived at the same visual design by convergent evolution. The spectral tuning of the rod and cone pigments of sharks is also discussed in relation to their visual ecology.
Keywords Shark – Colour vision – Microspectrophotometry – Cone – Visual pigment
