A new study published in The Anatomical Record suggests dolphins may use their teeth as sonar antennae, helping to explain how they hear and echolocate underwater.
“Our findings support the hypothesis that dolphins utilize their teeth as part of an advanced sound reception system,” Ryo Kodera at Tsurumi University in Japan told New Scientist. “This provides insight into how dentition may assist dolphins’ underwater life,” Kodera added.
Much like whiskers on cats, dolphins’ teeth may heighten sensitivity to movement, offering evidence for a 15-year-old theory that dolphins detect sonar signals through their teeth.
The study examined dolphin teeth and surrounding tissues, finding unique structures that distinguish them from other mammals. For example, dolphins have spongier alveolar bones and unusually large tooth sockets, allowing for greater tooth mobility. Nerve bundles connected to their teeth may serve sensory functions, enabling rapid signal transmission.
These findings align with earlier research. In October, UC Santa Cruz scientists discovered dolphins detect military sonar at much lower levels than regulators predicted. The study, published in Royal Society Open Science, observed 34 dolphin groups, revealing strong behavioral responses to sonar exposure, including avoidance and group reconfigurations.
Dolphins are highly social, sometimes gathering in groups of hundreds or thousands. With 42 species, some possessing up to 240 teeth, researchers continue to study how sonar affects dolphins, particularly in coastal areas like California, where military sonar operations are common. Such systems can disturb, harm, or even kill marine life.
