A new study on dolphin jaw anatomy suggests their teeth might function as true antennas for sound waves, enhancing their underwater echolocation abilities. This fascinating theory was detailed in research published in The Anatomical Record.
Ryo Kodera, a researcher from Tsurumi University in Japan and the study's lead author, explained, "Our findings support the hypothesis that dolphins use their teeth as part of an advanced sound reception system. This provides an important insight into how their dentition may be beneficial for aquatic life."
Dolphins, like other odontocetes (toothed cetaceans), have a unique dentition. Many of their teeth are not used for chewing, and the reason for their large number (some species have over 200 teeth) remains a mystery. However, scientists speculate that these teeth might be optimized for capturing sound waves.
Kodera and his team analyzed the jaws of various dolphin species, including the bottlenose dolphin (Tursiops truncatus), striped dolphin (Stenella coeruleoalba), and the false killer whale (Pseudorca crassidens). They also examined the jaws of domestic pigs (Sus scrofa domesticus) for comparison.
The analysis revealed several unique features of odontocete cetaceans: dolphin teeth are more "mobile" compared to those of terrestrial mammals and are embedded in spongy, porous dental sockets. Additionally, researchers discovered long, thick nerve fiber bundles connecting to the teeth through these porous structures.
"These fibers suggest significant sensitivity to tooth movement, along with a high capacity to perceive external stimuli," Kodera added. The analyzed nerve fibers have numerous sensory receptors at their ends and are wrapped in a thick layer of fat, allowing electrochemical signals to travel faster.
Their larger size compared to terrestrial mammal fibers may indicate that dolphin teeth are sensitive in a manner similar to the whiskers of some land animals. While the study's findings do not definitively establish the sensory function of these fibers, they represent an important step forward in understanding dolphin evolution and adaptation to marine life, opening new perspectives on how these remarkable animals interact with their environment.