Marine biologist Dr. Caine Delacy, who founded the "Just the Wild Expeditions" company through which OP had this incredible interaction with a sperm whale, has a story on his Instagram page discrediting the statement that sperm whale clicks can kill humans.

He also has a post explaining why sperm whale clicks are unlikely to harm humans, and that assertions that these clicks can kill humans are the result of the misinterpretation of sound measurements and thus ultimately lack scientific support:

1. Misunderstanding of Decibel Levels: The claim that sperm whale clicks can reach up to 230 decibels is misleading. Journalists lacking a fundamental understanding of units of measure popularized this figure, it is important to note that decibel measurements in water and air are not directly comparable. When adjusted for this difference, the sound in air would be approximately 169 decibels, which is loud but not necessarily lethal. It might cause harm only if someone were extremely close, possibly leading to eardrum damage.

2. Rare Occurrence of Extreme Decibel Levels: The loudest sperm whale clicks, exceeding 200 decibels, have been recorded only in rare instances. In general, their clicks are of lower intensity, making it even less likely that they could harm humans.

3. Sound as a Hunting Tool: Research by biologists, such as Fais et al. in 2016, suggests that sperm whales primarily use sound for echolocation and prey detection, not for killing or stunning prey. As they approach their prey, the intensity of their clicks decreases, and they rely on their teeth to capture the prey. This calls into question the notion that sperm whales use sound to harm animals.

4. Lack of Protective Mechanisms: If sperm whale clicks were indeed capable of damaging animal tissue or organs, it is essential to consider why sperm whales themselves do not suffer harm. This suggests that sperm whales do not possess protective mechanisms against their own sounds, further diminishing the idea that their clicks are deadly.

5. Complexity of Sound Phenomenon: Sound intensity and its effects are not solely determined by decibel measurements. Various factors, including direction, distance, and frequency of the sound, play a role in the impact it has. In most cases, these factors result in less rather than more harm to living organisms.

I would also bring up the lack of observations where sperm whales used their powerful echolocation clicks to defend against predation by various orcas. Sperm whales instead try to defend against orca attacks by going into a "rosette" formation (forming a circle with their heads together and their tail flukes fanned out) as well as attempting to dump excrement on the attacking orcas.

Marine biologist Dr. Caine Delacy, who founded the "Just the Wild Expeditions" company through which OP had this incredible interaction with a sperm whale, has a story on his Instagram page discrediting the statement that sperm whale clicks can kill humans.

He also has a post explaining why sperm whale clicks are unlikely to harm humans, and that assertions that these clicks can kill humans are the result of the misinterpretation of sound measurements and thus ultimately lack scientific support:

1. Misunderstanding of Decibel Levels: The claim that sperm whale clicks can reach up to 230 decibels is misleading. Journalists lacking a fundamental understanding of units of measure popularized this figure, it is important to note that decibel measurements in water and air are not directly comparable. When adjusted for this difference, the sound in air would be approximately 169 decibels, which is loud but not necessarily lethal. It might cause harm only if someone were extremely close, possibly leading to eardrum damage.

2. Rare Occurrence of Extreme Decibel Levels: The loudest sperm whale clicks, exceeding 200 decibels, have been recorded only in rare instances. In general, their clicks are of lower intensity, making it even less likely that they could harm humans.

3. Sound as a Hunting Tool: Research by biologists, such as Fais et al. in 2016, suggests that sperm whales primarily use sound for echolocation and prey detection, not for killing or stunning prey. As they approach their prey, the intensity of their clicks decreases, and they rely on their teeth to capture the prey. This calls into question the notion that sperm whales use sound to harm animals.

4. Lack of Protective Mechanisms: If sperm whale clicks were indeed capable of damaging animal tissue or organs, it is essential to consider why sperm whales themselves do not suffer harm. This suggests that sperm whales do not possess protective mechanisms against their own sounds, further diminishing the idea that their clicks are deadly.

5. Complexity of Sound Phenomenon: Sound intensity and its effects are not solely determined by decibel measurements. Various factors, including direction, distance, and frequency of the sound, play a role in the impact it has. In most cases, these factors result in less rather than more harm to living organisms.

I would also bring up the lack of observations where sperm whales used their powerful echolocation clicks to defend against predation by various orcas. Sperm whales instead try to defend against orca attacks by going into a "rosette" formation (forming a circle with their heads together and their tail flukes fanned out) as well as attempting to dump excrement on the attacking orcas.