Researchers Figured Out Why Ant Teeth Are So Sharp

Researchers from Pacific Northwest National Laboratory have investigated why some very small creatures can cut, puncture, and sting with such ease despite their small size. Researchers leveraged atomic-scale imaging to reveal minuscule details of how ants and other small creatures can use zinc to sharpen their various tools.The team showed for the first time how individual atoms of zinc are arranged on ant's teeth to maximize cutting efficiency and to maintain sharpness. Ants have teeth known as "mandibular teeth" that are on the outside of their mouths. Those teeth are made up of a material that tightly binds individual atoms of zinc in its construction.

Scientists discovered that over eight percent of the tooth weight is zinc. Researchers used a special microscope technique called atom probe tomography. That technique leverages an ion beam microscope to extract a tiny sample from the tip of the tooth. The sample was then imaged using atom probe tomography allowing the team to identify how the individual atoms were arranged at the tip of the tooth.

Researchers discovered that zinc was uniformly distributed in the tooth, which was surprising as scientists predicted zinc would be clustered in nano-nodules. The extreme sharpness of the ant teeth allows the ants to use 60 percent, and possibly even less, of the force that would be required if the teeth were made from material similar to that of human teeth.

One of the more interesting factoids researchers came up with is that the hardness of the teeth increases from approximately the hardness of plastic to the hardness of aluminum when zinc is added. The team notes that while there are harder engineered materials, they are also typically more brittle, giving a great mix of hardness and sharpness to the tiny creatures.