The most recognizable attribute of narwhals, cetaceans between four and five meters long that inhabit the Arctic seas, is undoubtedly their large tusk .
This oversized, helical-shaped canine can project more than two meters from the left side of its upper jaw, giving these animals a distinctive , unicorn-like appearance .
Now, a team of researchers coordinated by Martin Nweeia, an expert in biomaterials at the Harvard University School of Dental Medicine, has found that this piece helps the narwhal to perceive changes in its environment and determine, for example, if there is food or other specimens in the vicinity.
According to these scientists in the journal The Anatomical Record , there has been speculation about the functions of this tusk for decades, since these mammals, of which about 75,000 survive, have not been able to be thoroughly examined.
Thus, biologists agree that it is usually more present in males, who make use of it to confront others and position themselves in the social hierarchy.
Previous studies had revealed that it lacked enamel. Nweeeia and his collaborators have also found that the outer layer of the dental cementum of the tusk is porous and that the inner layer of dentin has microscopic canalizations that penetrate the structure.
In the center of it is the pulp, with nerve endings that are connected to the brain.
“Although it is a rigid part, it looks like a permeable membrane ,” Nweeia points out. This peculiarity makes it especially sensitive to temperatures and chemical changes in the environment.
For example, the heart rate of the animal experiences alterations if the tusk is exposed to different levels of salinity. The sensitive capacity of this piece would also allow males to locate females and know if they are willing to mate.
