A spider fang is a small wonder of engineering. If you're a venom-injecting arachnid—the kind that actively kills live, struggling prey*—the things you use to inject that venom need to be, on the one hand, thin enough to penetrate the external skeleton of your meal (usually an insect). But they also, however, need to be strong enough to execute that penetration without deforming or, worse, breaking.
There's a species of spider, researchers have found, that seems to have a struck that balance particularly well, via a particularly well-evolved fang—one that could serve as a model for the needles used by humans. A study published today in the journal Nature Communications explores the biomechanics of the fangs of Cupiennius salei (a wandering spider that lives mostly in South America). The paper's authors studied the fangs in detail, then modeled them—via both physical model and computer simulation—to subject them to varying conditions.
The findings? C. salei's fangs are curved. That distinguishes them from the biological injection needles of animals like mosquitos and bees, and allows the spiders not only to attack their prey from different directions, but also to hold them in place as they inject their venom. Think of it like a hollow fish hook.
