多年来，鲨鱼以其凶猛的血盆大口而出名，但现在科学家发现鲨鱼可怕的大嘴其实并不凶猛，甚至可以说是“懦弱无力”。相比之下，老虎和狮子的嘴就要厉害得多。相关论文发表在《生理学和生化动物学》（Physiological and Biochemical Zoology）杂志。
研究人员发现可怕的鲨鱼能用其非常锋利的牙齿撕咬猎物，但按照大小来说，鲨鱼的嘴不算厉害。负责此项研究的美国佛罗里达州坦帕大学的丹尼尔·胡伯说：“从体重来说，鲨鱼嘴咬得并不厉害。”胡伯博士及其小组通过研究10种不同的鲨鱼并测量其咬力之后得出这一结论。
研究人员通过敲击和电击它们来刺激其嘴部肌肉，从而测量它们的咬劲。他们发现鲨鱼能制造很大的破坏，因为其牙齿如此锋利且嘴巴又如此之大。论文中写道：“我们的分析表明，大型鲨鱼没有咬得太狠，但它们渐渐进化出了一个更大的头部。”研究表明，狮子和老虎的咬劲胜过了鲨鱼。不过，鲨鱼由于有较大的嘴，在水里占有优势。一条6米长的大白鲨可以咬穿你的身体，而许多动物得使用锯的动作才能撕裂猎物。胡伯博士表示，哺乳动物已经进化出了更加有效的嘴部肌肉。（生物谷Bioon.com）
生物谷推荐原始出处：
Physiological and Biochemical Zoology，DOI: 10.1086/588177，Daniel R. Huber ，Anthony Herrel
Is Extreme Bite Performance Associated with Extreme Morphologies in Sharks
Daniel R. Huber1,Julien M. Claes2 Jér?me Mallefet2 Anthony Herrel3,4
1Department of Biology, University of Tampa, 401 West Kennedy Boulevard, Box U, Tampa, Florida 33606; 2Marine Biology Lab (BMAR), Catholic University of Louvain, Batiment Kellner, niveau D-1, 3 place Croix du Sud, B-1348 Louvain-la-Neuve, Belgium; 3Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, Massachusetts 02138; 4Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Antwerpen, Belgium
Abstract
As top predators in many oceanic communities, sharks are known to eat large prey and are supposedly able to generate high bite forces. This notion has, however, largely gone untested due to the experimental intractability of these animals. For those species that have been investigated, it remains unclear whether their high bite forces are simply a consequence of their large body size or the result of diet-related adaptation. As aquatic poikilotherms, sharks can grow very large, making them ideal subjects with which to investigate the effects of body size on bite force. Relative bite-force capacity is often associated with changes in head shape because taller or wider heads can, for example, accommodate larger jaw muscles. Constraints on bite force in general may also be released by changes in tooth shape. For example, more pointed teeth may allow a predator to penetrate prey more effectively than blunt, pavementlike teeth. Our analyses show that large sharks do not bite hard for their body size, but they generally have larger heads. Head width is the best predictor of bite force across the species included in our study as indicated by a multiple regression model. Contrary to our predictions, sharks with relatively high bite forces for their body size also have relatively more pointed teeth at the front of the tooth row. Moreover, species including hard prey in their diet are characterized by high bite forces and narrow and pointed teeth at the jaw symphysis.
