在童话中,拉动圣诞老人雪橇领头的一只圣诞驯鹿名叫鲁道夫,它拥有一个独一无二的红鼻子,能像灯塔一样穿透迷雾更好的为圣诞老人领路。而现实中科学家们也发现驯鹿的一个特殊本领,它们能够看到紫外线以帮助自己更好的生存。
据国外媒体报道,研究者们发现,驯鹿能够看到大多数动物都看不到的太阳紫外线,这项本领能够有助它们在冰天雪地的极地环境中更好的生存。据了解,科学家们认为这种特殊视力能够让驯鹿及时发现隐藏的肉食动物,比如狼,从而提高生存几率。
领导此项研究的是伦敦大学的格伦-杰弗瑞(Glen Jeffery)教授,他说:“我们发现驯鹿不仅可以看到紫外线,而且能够利用这种本领来寻找食物和发现危险。”几乎所有的人类和其它哺乳动物根本无法看到紫外线,人类的眼睛角膜和水晶体会吸收紫外线阻止其接触到视网膜,而这样会导致角膜和水晶体损坏,导致雪盲症的发生。
人们能够看到的波长大约为400~700nm,而紫外线是电磁波谱中波长从10nm到400nm辐射的总称,不能引起人们的视觉。杰弗瑞教授的研究小组实验结果表明,驯鹿能够看到320~350nm的波长。除了能够减少紫外线伤害避免雪盲症的发生之外,并且在白茫茫的雪地中,动物的尿液和毛皮都能够吸收紫外线,这样一来驯鹿就能够比较容易发现捕食者的存在。据了解,该项研究的结果已发表在《实验生物学期刊》(Journal of Experimental Biology)中。(生物谷Bioon.com)
生物谷推荐原文出处:
The Journal of Experimental Biology DOI: 10.1242/?jeb.053553
Arctic reindeer extend their visual range into the ultraviolet
Christopher Hogg, Magella Neveu, Karl-Arne Stokkan, Lars Folkow, Phillippa Cottrill, Ronald Douglas, David M. Hunt and Glen Jeffery
The Arctic has extreme seasonal changes in light levels and is proportionally UV-rich because of scattering of the shorter wavelengths and their reflection from snow and ice. Here we show that the cornea and lens in Arctic reindeer do not block all UV and that the retina responds electrophysiologically to these wavelengths. Both rod and cone photoreceptors respond to UV at low-intensity stimulation. Retinal RNA extraction and in vitro opsin expression show that the response to UV is not mediated by a specific UV photoreceptor mechanism. Reindeer thus extend their visual range into the short wavelengths characteristic of the winter environment and periods of extended twilight present in spring and autumn. A specific advantage of this short-wavelength vision is the use of potential information caused by differential UV reflections known to occur in both Arctic vegetation and different types of snow. UV is normally highly damaging to the retina, resulting in photoreceptor degeneration. Because such damage appears not to occur in these animals, they may have evolved retinal mechanisms protecting against extreme UV exposure present in the daylight found in the snow-covered late winter environment.