Sperm Whale Echolocation: Master Navigators of the Deep
Cover Image Credit: SDM Diving
Sperm whales (Physeter macrocephalus) are the largest member of the toothed whale family and are widespread throughout the world’s oceans. Unlike humpback and some other baleen whale species, sperm whales largely are not succumbed to the long annual migration to winter breeding grounds. Taking time away from feeding grounds. These whales travel as they need – wherever food is available and feed daily.
Sexually Dimorphic
Sperm whales are sexually dimorphic and become separated between latitudes once males reach sexual maturity. Females and young males will generally inhabit higher latitude grounds whilst the mature males (bulls) will usually become solitary and venture south and live in lower latitude. Reintroducing themselves into higher latitudes periodically to breed and socialise with the females.
Figure 1: Diagram visual of inside Sperm whale’s head.
Biology of Echolocation
The sperm whale has a uniquely shaped body. Characterized by a large, block-shaped head that accounts for roughly one-quarter to one-third of its total body length. This distinct morphology has evolved to support the whale’s ability to hunt in deep, dark ocean environments. Also to maintain acoustic communication with others after long dives.
The species derives its name from the spermaceti organ, which contains a waxy, oily substance, resembling the consistency of sperm. This organ plays a key role in sound production and echolocation. It can hold up to 1900 litres of spermaceti oil—a mixture of triglycerides and wax esters. Remarkably, the speed of sound in spermaceti is about 2,684 metres/s (at 40 kHz and 36 °C). Nearly twice as fast than in the melon of dolphins.
Spermaceti Organ
Beneath the spermaceti organ lies the “junk” or melon, made up of compartments of spermaceti separated by connective tissue and cartilage. Two air passages run through the whale’s head. The left passage leads directly to the blowhole, while the right passage runs beneath the spermaceti organ. Passing through a pair of phonic lips and into a structure called the distal sac, located at the front of the nose. The distal sac connects both to the blowhole and the end of the left air passage.
A Sperm Whale Acoustic Lens
Echolocation clicks are generated when the whale closes its blowhole when diving and forces air through the phonic lips. Producing a focused beam of broadband sound. The click travels backward through the spermaceti organ and reflects off the frontal sac at the front of the skull. This reflection redirects the sound into the melon, which acts as an acoustic lens to focus the outgoing click. Some of the sound energy also reflects back through the spermaceti organ toward the front of the head. Where it undergoes additional reflections.
Sperm Whale Clicks
This rapid sequence of reflections—occurring over just milliseconds—creates the characteristic multi-pulse structure of sperm whale clicks. The frontal sac, which lines the concave front of the cranium. It has a knobbly posterior wall covered in fluid-filled knobs and grooves. These knobs effectively reflect incoming sound waves, while the grooves trap a thin film of air. This air layer remains stable regardless of the whale’s depth or orientation. Creating a highly efficient sound mirror.
Echoes from the emitted clicks are primarily received through the lower jaw. A continuous, fat-filled canal within the jaw transmits the returning acoustic signals directly to the inner ear. Completing the whale’s sophisticated echolocation system.
Vocalisations
Sperm whales produce a distinct type of echolocation click. Typically used in prey search, within the 10 Hz–30 kHz frequency range. These clicks can reach sound pressure levels of up to 236 dB. Making them the loudest known vocalisation of any animal, and are detectable over distances of more than 15 kilometres. During foraging, sperm whales emit long sequences of regular clicks at intervals of 0.5 to 2 seconds. Interspersed with rapid click trains known as “creaks.” Creaks – high-frequency bursts resembling the sound of a creaky door hinge. These are typically produced during the final stages of prey pursuit.
Acoustic Characteristics
According to Madsen et al., the acoustic characteristics and low repetition rate of usual clicks are well-suited for long-range echolocation. While creak clicks function similarly to the terminal buzzes of echolocating bats during prey capture. Usual clicks can provide information about prey aggregations up to 16 km away. Whilst creak clicks are effective at ranges of around 6 km.
Calves and Clicks
A study by Tonnerson et al. used sound and movement recording tags on three first-year sperm whale calves over a total of 15 hours. The data showed that the calves rarely produced codas—social clicks typically used in adult communication. Likely oriented themselves using the passive acoustic cues from nearby clicking adults.
Independent Foraging
The calves demonstrated well-developed diving abilities (maximum depths of 285, 337, and 662 m; dive durations up to 44 minutes) and emitted clicks indicative of echolocation. One calf, which performed the deepest and longest dives. Also produced two echolocation buzzes, suggesting a possible attempt at independent foraging. These findings imply that sperm whale calves may begin supplementing their milk diet. With self-caught prey at a younger age than previously thought.
Odontocete Species
Across odontocete species, there is a general correlation between body size and the inter-click interval (ICI) of echolocation clicks. This relationship is likely linked to prey detection range. As a longer interval allows time for echoes from distant objects to return before another click is emitted. As a result the ability for larger whales to scan large volumes of deep water enables them to locate calorie rich prey. Supporting their substantial energetic needs.
Foraging
Sperm whales spend over 70% of their time foraging alone. Typically diving to depths between 300 and 800 metres. Though they can reach depths of 1000 to 2000 metres. These dives, which can last over an hour, take place in the mesopelagic and bathypelagic zones along continental shelf edges. While they feed on a variety of species; including giant squid, colossal squid, octopus, demersal rays, and sharks. Their diet primarily consists of medium-sized squid, often consuming 1000kg per day!
Acoustic Reflections
In a different study by Tonnerson et al., sound-recording tags were placed on the tips of three sperm whales’ noses. One recording captured over 6000 acoustic reflections from organisms up to 144 metres in front of the whale. Supporting the idea that sperm whales use echolocation for long-range prey detection. The whale demonstrated a stable, long-range acoustic “gaze.” Indicating continuous assessment of its environment to locate food sources.
In the same study, a male sperm whale was observed maintaining high inter-click intervals. Allowing for an extended acoustic field of view. This strategy supports the whale’s capacity to scan large volumes of water and evaluate the acoustic environment continuously.
Timing of Clicks
Previously, it was hypothesised that sperm whales might use powerful echolocation clicks to stun their prey. However, Tonnerson’s findings revealed that buzzes—rapid click sequences. Used in the final stages of prey pursuit—were initiated more than 20 metres away from prey. This distance suggests that sperm whales do not immobilise prey with sound. Instead, they sacrifice signal strength for higher temporal resolution to precisely track prey movement.
Compared to beaked whales, who begin buzzing at about one body length from prey. Sperm whales initiate buzzing at four times that distance (in body lengths). This likely reflects differences in manoeuvrability. Sperm whales, being larger and slower-turning. They need earlier updates to plan their movements effectively.
Environmental Navigation
Beyond prey detection, sperm whales also use their powerful biosonar to navigate their environment. Echoes from the seafloor serve as bathymetric landmarks. This helps the whales orient themselves within prey-rich areas. This advanced sensory ability gives sperm whales an edge over other deep-diving toothed whales. Whose shorter sonar ranges likely force them to rely more heavily on predictable, stable prey distributions. Thus limit their suitable habitats.
Sperm Whales in Bremer Bay
On our Killer Whale Expeditions out of Bremer Bay, we regularly encounter sperm whales. Calm, flat days are the perfect opportunity to spot these toothed predators. Identifying their distinct 45-degree angled blow from their blowhole positioned off to the left side of their rostrum. On charter, crew have seen a wide range of behaviours exhibited. From the solitary individuals that may be logging at the surface catching their breath between dives. To expansive maternal pods of females and young individuals reconnecting with each other at the surface. Communicating through breaches and tail slaps… every moment with this prehistoric looking beast is incredible.
Bremer Bay and The Sub Basin
We have even been so lucky on charter in our 2024 season. A pod of sperm whales were chased into shallow waters and pushed up on top of the continental shelf by a few pods of orca. The crew were left speechless as nothing of this magnitude and intensity had been seen before in the area between these species.
Other Encounters
There had been previous encounters where orca had harassed sperm whales after they’ve surfaced from dives to steal prey from their mouths. But not a surge lasting over 20 minutes. After the surge, the group of sperm whales rose to the surface and in retaliation to the orca, formed a ‘rosette’.
Rosette Formation
A rosette formation is where the whales gather in a circular shape. Tails facing outward and often put younger individuals or calves in the middle, defending them from predators or harm. The adults then exhibited ‘defence defecation’. Expelling faecal matter into the water and swishing it around with their tails to deter the orca from proceeding with further action. It worked! The orca after performing a symphony of tail slaps and swift manoeuvres around the whales ceased their attack. However some did end up with a bit of meat. We couldn’t conclude if the meat possessed was taken from the whales. But such an event was amazing to witness!
Image: Naturaliste Charters Sperm Whale Under Attack from Orca – Form a Rosette
Naturaliste Charters Killer Whale Expeditions
If you are someone who is interested in the potential of seeing these incredible animals in the wild. Naturaliste Charters in Bremer Bay are the perfect local opportunity to do so. December and April are our most reliable months to spot these predators off the continental shelf, you will not regret it.
References
1. Miller P. J. O., Johnson M. P. Tyack P. L. (2004) Sperm whale behaviour indicates the use of echolocation click buzzes ‘creaks’ in prey captureProc. R. Soc. Lond. B.2712239–2247http://doi.org/10.1098/rspb.2004.2863
2. Madsen, .P., Wahlberg, .M. & Møhl, .B. Male sperm whale (Physeter macrocephalus) acoustics in a high-latitude habitat: implications for echolocation and communication. Behav Ecol Sociobiol 53, 31–41 (2002). https://doi.org/10.1007/s00265-002-0548-1
3. Fais, A., Aguilar Soto, N., Johnson, M. et al. Sperm whale echolocation behaviour reveals a directed, prior-based search strategy informed by prey distribution. Behav Ecol Sociobiol 69, 663–674 (2015). https://doi.org/10.1007/s00265-015-1877-1
4. Tønnesen Pernille, Oliveira Cláudia, Johnson Mark, Madsen Peter Teglberg, (2020) The long-range echo scene of the sperm whale biosonarBiol. Lett.1620200134. https://doi.org/10.1098/rsbl.2020.0134
5. Tønnesen, P., Gero, S., Ladegaard, M. et al. First-year sperm whale calves echolocate and perform long, deep dives. Behav Ecol Sociobiol 72, 165 (2018). https://doi.org/10.1007/s00265-018-2570-y
6. Solsona-Berga, A., Posdaljian, N., Hildebrand, J.A. and Baumann-Pickering, S. (2022), Echolocation repetition rate as a proxy to monitor population structure and dynamics of sperm whales. Remote Sens Ecol Conserv, 8: 827-840. https://doi.org/10.1002/rse2.278
7. André, M., Caballé, A., van der Schaar, M. et al. Sperm whale long-range echolocation sounds revealed by ANTARES, a deep-sea neutrino telescope. Sci Rep 7, 45517 (2017). https://doi.org/10.1038/srep45517
