Can the Teeth of Dolphins Help Them To Hear Underwater?

Dolphins are known to be highly intelligent mammals. New research has looked into the possibility that the teeth of dolphins help them to hear underwater. Dolphins rely heavily on echolocation, with the researchers aiming to find out if dolphins’ teeth are linked to this.

New research has looked into the anatomy of a dolphin’s jaw, which suggests that their teeth may help them to hear underwater [1].

This research suggests that the teeth of dolphins play a key role in their ability to excel in underwater life, and explain how they use and hear echolocation underwater [1].

Finding out more about how teeth impact various animals is always interesting, and provides scientists with more of an understanding of how teeth affect the world around us.

Dolphins’ teeth

The average human has 32 teeth in adulthood. However, this pales in comparison to some dolphins – with some species having as many as 240 teeth [2]!

Many animals use different parts of their body to improve their feelings and senses. For example, cats use their whiskers to improve their sensitivity to movement.

Dolphins are known to be highly intelligent. They rely heavily on echolocation – which refers to when animals use sound to navigate when their vision is limited.

For dolphins, echolocation is very important. Interestingly, scientists have long suspected that the teeth of dolphins may be linked to echolocation. Researchers sought to look into this further.

The Research

The research was carried out by a team of Japanese researchers from Tsurumi University in Japan. Their findings have been published in The Anatomical Record journal [1].

The researchers used a sample of dolphin teeth and surrounding tissues for their study [1]. This involved the team studying and examining them in detail.

The team also wanted to compare the teeth and surrounding tissues to other animals, which would provide them with greater insights into dolphins’ teeth.

The researchers were able to find unique structures among these teeth and tissues [1]. These various unique structures assist dolphins significantly and contribute towards their intelligence.

Among the unique structures was dolphins’ spongier alveolar bones – which is the bone that contains the tooth sockets [1]. Moreover, they observed that dolphins have unusually large tooth sockets.

Furthermore, a unique ligament structure was identified. They noted that fibers in the inner layer of the ligaments spread out from the root of the tooth [1].

While this particular structure is somewhat common in mammals, there was something unique – with some fibers ending in structures that look like sensory receptors, which allow signals to travel through the fibers at a rapid pace [1].

The nerves therefore enable rapid signal transmission. This shows the impact that their teeth have, as they can assist echolocation.

Furthermore, the researchers saw that nerves connected to their teeth may assist with sensory functions [1].

Therefore, the researchers concluded that these various structures all help to facilitate greater tooth mobility. This helps dolphins’ teeth to serve a sensory purpose [1].

Overall, this confirms the idea that the teeth of dolphins do indeed contribute, and play a key part in, the process of echolocation [1]. Therefore, this allows them to hear underwater.

Author comments

These are very interesting findings, and underline the effect that the teeth of dolphins have. They clearly contribute towards their intelligence.

The findings are consistent with research from October, when a separate research team found that dolphins detect military sonar at much lower levels – aiding their response to sound [3].

Ryo Kodera was the lead author pf the research, and commented on the findings. Kodera says that “our findings support the hypothesis that dolphins utilize their teeth as part of an advanced sound reception system” [4].

Continuing, Kodera says that “this provides insight into how dentition may assist dolphins’ underwater life” [4]. The team were pleased to confirm their hypothesis, which has improved their knowledge of dolphins.

Finding out more about how the teeth of mammals assist in their lives is always interesting. While the focus is usually on human teeth, this research underlines how the teeth of mammals are worth studying!

Thinking points…

[1] Can you imagine having to look after 240 teeth?! Fortunately for us humans, the maximum number we need to look after is 32. But it is crucial to do so! One of the best ways of helping towards this is to attend regular dental check-ups, as these allow a dentist to take a thorough look at your oral health. We recommend booking an appointment now!

[2] This research is very interesting, and adds to our understanding of dolphins. Do you know anyone who loves dolphins, or underwater species in general? If so, this research may be of interest to them. You could send this article to them, or share this article on your social media channels! We would love you to share this article now!

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References

[1] Kodera, R., Kajinishi, Y., Uekusa, Y., et al. (2024). Morphological characteristics of the unique periodontal structure in dolphins. The Anatomical Record. DOI: https://doi.org/10.1002/ar.25601.

[2] McCall, R. (2024). Do Dolphins’ Teeth Help Them Hear Underwater?. Available: https://www.iflscience.com/do-dolphins-teeth-help-them-hear-underwater-77395. Last accessed: 1st January 2025.

[3] Southall, B. L. , Durban, J. W., Calambokidis, J., et al. (2024). Behavioural responses of common dolphins to naval sonar. Royal Society Open Science. 11 (10). DOI: https://doi.org/10.1098/rsos.240650.

[4] Oral Health. (2024). Study: Dolphins’ teeth may act as antennae for sound waves. Available: https://www.oralhealthgroup.com/oral-health/study-dolphins-teeth-may-act-as-antennae-for-sound-waves-1003983378/. Last accessed: 1st January 2025.