只有蜥蜴的大小与它的咬合力有关. 图片©Matt Cornish/Shutterstock

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Biting force in lizards and their close relatives is largely a matter of size.

Even the most carnivorous lizard can bite no harder than herbivores of the same size, 真实赌钱App下载研究人员发现.

When lizards fight or feed, the amount of biting force they use is closely related to their size.

尽管头骨的形状各不相同, tooth types, lifestyles, 以及蜥蜴和相关爬行动物的栖息地, research published by scientists at the Museum has found that size is the best predictor of how forcefully the animals can bite. 

This link could have implications for what we know about the evolution of lizards, suggesting selection on their body size is linked closely to selection on bite force.

It might also help us to predict the abilities of their ancient relatives, 甚至其他爬行动物,比如 dinosaurs

娜塔莉·库珀博士, 真实赌钱App下载的高级研究员和这项研究的合著者, says, “不同的蜥蜴咬人的力度差别很大. 很明显,体型越大咬得越有力, 但之前的许多研究已经从理论上证明了其他特征, 比如饮食和生活方式, 应该同样重要. 然而,真实赌钱App下载没有找到任何证据.'

The scientists have called for more research to expand upon their findings, published in 英国皇家学会学报B, to assess if what they found holds true for other lizard species.  

Two Bosc's fringe-toed lizards engage in a courtship ritual involving biting

Biting can be used for many purposes in lizards, including courtship rituals. 图片©查尔斯J. 下许可的锋利, CC BY-SA 4.0 via 维基共享


除了吃, 蜥蜴的嘴有各种各样的用途, 包括战斗, 捕捉猎物, 保卫配偶. Having greater bite force might allow a lizard to tackle prey and eat food it otherwise could not, 使咬合力成为自然选择的重要组成部分. 

Co-author 马克·琼斯博士 explains, 'In the past, people have used sprint speed and running endurance as a measure of an animal's performance, 但是咬合力现在也变得很重要.

'It is a physiological behaviour that can be quantified and related to various aspects of ecology that are related to survival. It's important to the animal as an individual, but also the ecology of its species.'

While studies have been carried out on the bite of individual species, 或小群体, a wider look at how bite force varies across a major group hadn’t been carried out. 这项研究试图改变这一现状. 

The researchers decided to focus their analysis on a group of reptiles known as the Lepidosauria, 其中包括蜥蜴, limbless reptiles known as amphisbaenians and lizard-like animals called tuatara. 该小组还包括 snakes, but these were excluded from the study as few studies have sampled the bite force of these animals.

Lead author Justin Isip, 真实赌钱App下载的博士生, says, 'The lepidosaurs are interesting as they show greater variation in diet than most people assume and even include some unusual specialised species that that feed on a diet of snails.

'There has also been a lot of previous research into bite force in this group for us to build on.' 

领先于他们的研究, the scientists predicted that bite force would be greater in larger species, herbivores, non-burrowers and animals with teeth attached firmly to the jaw bone's crest. Following its completion, they found that only size was borne out in the data. 


Skinks, 比如这个人, 体型和咬合力不符合总体趋势吗. 图片©Kurit afshen/Shutterstock


使用了20多年的数据, the researchers looked at how bite force was affected by different traits such as diet, 头部尺寸及种类.

这被用来创建一系列的模型, 然后可以用来检验他们所做的预测.

总的来说,咬合力的主要差异是由大小决定的. 较大的动物有较大的颚肌, increasing the force they can exert with their mouth relative to their body size.

这种关系甚至适用于样本中的食草动物, which was unexpected as previous studies suggested they had more forceful bites than both carnivores and omnivores.

'I think the answer for the herbivory question was interesting because it's discussed a lot in scientific literature,娜塔莉说, 'but it has never been tested using so many species so it was quite exciting to get a negative result. It showed that herbivores bite more forcefully because they're big, not because they eat plants.'

However, some types of lizard didn't neatly follow the size bite-force pattern. Skinks, 分布广泛的蜥蜴群, 根据头部尺寸而不是身体尺寸来匹配图案.

Burrowers, meanwhile, bite more forcefully than expected for their head dimensions. It had been suggested that because these animals need to push themselves through the soil, bite force would be reduced as the lizards adapt to have smaller heads. 

Instead, these results suggest that they can continue to exert a lot of force even with small heads. The researchers suggested that bite force in burrowers might be particularly important to break apart prey before swallowing, as their smaller heads have limited gape and cannot swallow large food whole.

Though the findings have important implications for our knowledge of lizards, 需要做更多的工作来增加这一主题的可用数据. 这是迄今为止同类研究中规模最大的一次, 但只有大约2%的蜥蜴有咬合力数据.

This is because some species are too small or not aggressive enough to be easily sampled, 而其他许多人从未被研究过.

科学家们希望进行进一步的研究, 以及让正确的数据更加免费的努力, will be able to present a clearer picture of how biting adaptations affect lepidosaurs.

还有很多其他群体, 比如小型食草动物, 这一点还没有被研究或研究不足,贾斯汀说. 'It would be good to get bite force data from these in the future to develop our understanding further.'