The sharp science behind fangs, the ultimate biting weapon

The thought of piercing and venomous viper bites and the stabby sting from a wasp are part of what makes spooky season just so creepy. They make our skin crawl for good reason, as thousands of years of evolution have implanted fear of creepy crawly critters like snakes and spiders in most humans largely because of the threat that their bites pose.

However, these scary fangs, stingers, thorns are biological tools that animals use to defend themselves and can help humans develop more “pierce resistant” materials. In a new paper out today in the Journal of the Royal Society Interface, a team of researchers detail a model that can calculate the energetics, or how the energy behind the action of puncturing works when one organism stabs another.

[Related: The best remedy for a snakebite: carry car keys.]

“The idea behind this was to come up with a quantitative framework for comparing a variety of biological puncture systems with each other,” Philip Anderson, a University of Illinois Urbana-Champaign professor of evolution, ecology, and behavior who led the research, said in a press release. “An initial question of this research was how do we even measure these different systems to make them comparable.”

Animals and plants use a variety of puncture strategies for both stabbing prey or defending themselves from predators, including stinging the way bees do and biting like snakes. However, even those that use similar strategies or tools can customize those tools to meet their specific needs and different targets, according to the researchers.

“In vipers, for example, some bite mammals, which means they must puncture through soft tissues encased in skin, while others target reptiles, which have scales, making them stiffer and harder to pierce,” said Anderson, who studies the mechanics and energetics of biological puncturing systems.

On the other hand, parasitoid wasps may use their ovipositors, a tube-like organ used to lay eggs, to also help them burrow through the hides of caterpillars but can penetrate fruit or even wood.

“It’s a challenging problem to predict the properties of biological systems,” Bingyang Zhang, a postdoctoral researcher who worked on this paper, said in a press release.

[Related: Why some bees and wasps are more likely to sting you.]

To develop a model that can be applied to multiple biological systems, Zhang determined that there are the key factors that must be included in any calculations of the energetics involved in the action of puncturing. These factors include changes in the kinetic energy (or motion) as the puncturing tool is used and the material that is the intended target, such as whether it is a scaly reptile or a hairy mammal.

The new model is being deployed to help better understand puncturing organisms like viper fangs, stingray spines and parasitoid wasp ovipositors.  

“If we know the morphology or the shape of the damage created by a puncture tool, we can use this model to predict how much energy was expended during a puncture scenario,” Zhang said. “Or we can predict different aspects of the material’s property, for example, how it will fracture, which will be useful in both engineering and biological applications.”