Title: Narwhal tusk - Scientists finally solve its real purpose | Tech Times
Headings: Narwhal tusk - Scientists finally solve its real purpose
Narwhal tusk - Scientists finally solve its real purpose
Content: Some biologists believed the horns are used for ice picks, while others said the horns picked up noises deep under water. Researchers discovered the horn is, in fact, used as a sensory organ. Unlike most mammal teeth, the horn of a narwhal is not protected by enamel. Sea water enters the horn through cementum channels, which are also present in human teeth. The liquid then travels through a network of tubules to the center of the tooth, heading base of the tusk. There, the water excites nerve endings in the pulp of the tooth, sending signals to the brain of the animal. This makes the horn sensitive to temperatures and the animal can "taste" the concentrations of different chemicals in the water. Biologists believe the males may use the horn to find food, as well as females who may be ready to mate. "The combined evidence suggests multiple tusk functions may have driven the tooth organ system's evolutionary development and persistence," researchers wrote in the study. Martin Nweeia from the Harvard School of Dental Medicine led the study.