Click production during breathing in a sperm whale (Physeter macrocephalus)

Area of Science:

• Marine Biology
• Bioacoustics
• Cetacean Research

Background:

• Sperm whales (Physeter macrocephalus) are deep-diving toothed whales known for their complex vocalizations.
• Understanding the sound production mechanisms in cetaceans is crucial for bioacoustics and conservation efforts.
• Previous research has focused on the general anatomy of sperm whale sound production, but simultaneous breathing and clicking have not been directly observed.

Purpose of the Study:

• To investigate the physiological mechanisms enabling sperm whales to produce clicks while simultaneously ventilating their lungs.
• To determine the specific anatomical structures involved in this unique capability.
• To compare this mechanism with sound production in other odontocetes.

Main Methods:

• Observation of a sperm whale at the surface using above- and underwater video.
• Synchronized underwater sound recordings during vocalizations and ventilation.
• Analysis of the whale's respiratory and clicking behaviors.

Main Results:

• Seven instances were recorded where the sperm whale ventilated its lungs while producing clicks.
• Inferred that click production involves pressurizing air in the right nasal passage, which is separate from the lungs and left nasal passage.
• Observed air flow anteriorly through the phonic lips into the distal air sac.

Conclusions:

• Sperm whales possess a unique physiological adaptation allowing simultaneous breathing and clicking.
• This capability is attributed to the specialized and asymmetric nasal and air sac system within the sperm whale's forehead.
• This finding highlights the distinctiveness of sperm whale bioacoustics within the Odontoceti suborder.