Having evolved for the past 38 million years suspended underwater, the way that whales engage with, and use sound is unimaginably different from how humans interact with sound in our terrestrial surroundings.  Surprisingly, whales originally evolved from a land mammal. Since their development under the sea however, the structures responsible for sound creation and perception in whales has changed significantly. In contrast to many terrestrial species that depend mostly on a combination of visual, olfactory and auditory cues, whales rely primarily on sound to navigate, to develop social bonds, and for the purpose of foraging through the depths of the ocean.

Sound is such a vital component of a whale’s reality also due to how easily sound vibrations move through the water — they travel 4x faster in water than vibrations produced in the air! Not only can signals be sent quickly to communicate with other whales or family members, but some sounds produced under water can be heard from miles away. This allows whales to move or make decisions as a collective, without needing to maintain visual contact with each other. The underwater speed of sound also helps whales detect elusive prey — sometimes with the help of echolocation, as in the case of toothed whales.

Sound is what ties whales to their reality, it’s how they perceive shapes and movements. Sound is for whales what our vision or sense of smell is for us. They use sound to investigate the shape of a rock where we would run our fingers along its edges. Sound is how whales engage with the world that surrounds them. Although we cannot understand what is being perceived or shared between whales, we also cannot underestimate how important sound may be for their understanding of the ocean, or of each other.

Baleen Whales & Sound

Baleen whales produce low-frequency calls, such as moans, songs, and calls that can travel hundreds of miles underwater.  They produce sound more akin to humans and other terrestrial mammals, and pass air over their vocal folds. Unlike terrestrial mammals however, baleen whales are able to create sound while holding their breath. For as long as 15-20 minutes for example, humpbacks can sing without releasing any air from either their mouths or blowholes by recycling air through their vocal structures.

  • Baleen whales produce low-frequency (20-300Hz) moans, calls, and songs that can travel hundreds of miles underwater using the same principles for sound production as with humans and land mammals, but with some key adaptations.
  • They do not have vocal cords. Instead, they use unique structures in their larynx called the U-fold and Cricoid Cushion (a fat cushion). The U-fold is lined with muscular folds called Transverse Arytenoid Folds. To vocalize, baleen whales pass air from the lungs, through the larynx, and into a laryngeal air sac. This air does not escape through the blowhole. As the air passes through the larynx, it vibrates the U-fold, and adjacent fat cushion, and this is what generates sound.
  • Since they do not exhale while making sounds, Air passes into the laryngeal air sac, and can be recycled back and forth to the lungs to allow for prolonged bouts of vocalizations.

  • Moving air from the lungs, through the larynx, and back has inherent anatomy constraints due to the pressure of the water that impacts how deep into the water baleen whales can vocalize.
  • At depths of about 30m, calls can last a maximum of about 15 seconds, and low frequency calls (to a maximum of about 300Hz) can only be produced to diving depths up to 100m.
  • Continuous vocalizations of >10s in humpback whales are typically produced close to the surface at depths of less than 20m, including humpback whale song.
  • These frequencies and depths overlap with vessels noise, which today dominates the range of 30–300Hz near the ocean surface. This overlap in essential frequencies for communication and human made noise pollution highlights how baleen whale communication can be severely masked by vessel noise.

  • Baleen whales lack external ear openings, and it is thought that the head itself acts like a sound reception tool, collecting sound waves from the surrounding ocean.
  • Low-frequency sounds (infrasound) are channeled through their skull bones into the inner ear (cochlea).
  • The more turns in the cochlea is thought to allow for lower frequency hearing. Baleen whales are understood to have more turns in their cochleas when compared to toothed whales, as they rely on lower frequencies.

  • Humpback Whales, along with right whales and bowhead whales, are able to vocalize at a wider frequency range than other baleen whales. Humpbacks commonly vocalize between 40 – 600Hz but can reach as high as 6kHz.
  • These higher frequency sounds are possible from additional vibrations among thicker Transverse Arytenoid Folds (TAFs), in addition to vibrations between the TAFs and the Cricoid Cushion.
  • This increased range allows for more complex communication across a wider frequency range – like the humpback song.

Humpback Social Calls

Humpback Song 2023

Bubble Net Feeding

Toothed Whales & Sound

Toothed whales produce high-frequency clicks, whistles, and pulsed calls, mainly for echolocation and communication. They produce sound by passing air through a structure in the nasal cavity called the phonic lips. This movement through the phonic lips causes vibrations in surrounding tissues which pass into the melon – a fatty organ in the forehead of toothed whales. From there, the vibrations are projected outwards outwards with both control and accuracy, creating sounds in the water.

  • Toothed whales do not use vocal folds or their larynx to make sound; instead, they generate sound by passing air between differently pressurized air sacs on either side of a structure in the nasal cavity called the phonic lips, roughly 20mm -70mm below the blowhole.
  • Pressurized air travels between the air sacs that surround the nasal passage and is pushed through the phonic lips causing vibrations in surrounding tissues.
  • These vibrations are then directed through a fatty structure called the melon, which focuses and projects the sound forward.
  • The amount of time the phonic lips are open as air passes through controls whether they produce short echolocation clicks, longer bursts of calls, or whistles.
  • Toothed whales, like orcas, can echolocate. They emit quick, high frequency clicks by rapidly closing their phonic lips. When the sound waves from these clicks bounce off other objects in the ocean, the returning sound waves and vibrations provide information about the size, shape, and distance of objects.
  • Toothed whales can vocalize and echolocate in very deep water because sound production occurs in the nasal cavity. The skull around the nasal cavity protects the air sacs and phonic lips, acting as a pressure stabilizer and enabling deep water communication and foraging.

  • The heads of toothed whales act as an acoustic antenna, collecting sound from the surrounding ocean.
  • Sound waves are channeled through the bones and fat-filled cavities in the lower jaw and towards the auditory bulla (inner ear).
  • These vibrations are transmitted to the cochlea, a spiral-shaped organ in the inner ear.
  • The inner ears face forwards, and this position is thought to assist whales determining where a sound has come from.

Resident Orca – A Clan

Resident Orca – BCD Clans

Transient Orca