Snakes are misunderstood. They’re not slimy. They’re not ___1___ by music. And the poisonous ones don’t all ___2___ venom into their prey through hollow needlelike fangs. In fact, the fangs of most toxic serpents have external grooves that direct the flow of poison. And the venom’s viscosity is key to getting it where it needs to go. So says a study in the journal Physical Review Letters. [Citation to come.]

Ok, some snakes do use the ‘hollow fang trick’ to take care of their prey. Rattlesnakes, for example. But most snakes have solid fangs, which they use to punch holes in their victims’ skin before they let the venom fly—or slide. Those fangs tend to have grooves that help ___3___. But scientists got to wondering how that approach could be effective. Couldn’t struggling prey simply ___4___ the poison as it trickles?

Turns out that the venom’s viscosity keeps it ___5___ in the groove. And when a fang penetrates the victim’s tissue, the groove makes a canal that generates suction. That suction pulls the venom into the wound. But it also makes the venom less viscous, allowing it to move even faster into the prey. Because getting bitten by a snake sucks.
【视听版科学小组荣誉出品】
charmed inject direct the flow brush off nestled
人们误会蛇了,其实它们并不粘,也不会被音乐吸引,而且并不是所有毒蛇都会通过针状中空的毒牙向猎物注射毒液。绝大部分毒蛇的毒牙外部都有凹槽,可以引导毒液流向。而毒液的黏性则是毒液流向的关键所在。这项研究刊登在《物理评论快报》期刊上。 有些蛇确实利用它们的中空毒牙毒液来压制猎物,比如说响尾蛇。但大部分的蛇都会在毒液溅出来之前用它们坚固的毒牙在猎物身上凿洞。而毒牙外部的凹槽能引导毒液流向。科学家们有疑问了,毒液那么粘流速那么慢,这样一来猎物挣扎的时候不会把毒液甩走么? 原来,由于毒液的黏性,毒液得以停留在凹槽里面。毒牙穿透猎物组织的时候,凹槽就成了一个泵,毒液就被推入伤口里了。同时,毒液的黏性也大大降低,流速也快了很多。被蛇咬一口日子可不好过~