In the mid-1800s, soon after American whaling ships began operating in the North Pacific, an interesting trend emerged. Whalers saw a 58% drop in their successful strikes within just a few years. Sperm whales in the region had suddenly become much harder to kill. Generally, when predators like orcas are nearby, sperm whales protect their most vulnerable by forming defensive circles at the surface. But this behavior made them susceptible to whaling ships. It seems that sperm whales in the North Pacific were somehow able to quickly adapt to this reality. Groups that likely hadn’t yet experienced human attacks began escaping whaling boats on fast currents instead of forming defensive circles. And, based on what we’re starting to understand about sperm whales, it seems possible they were actually broadcasting survival strategies to one another.
Indeed, unbeknownst to whalers, spermaceti, the material they killed for, is an essential part of the sperm whale’s sophisticated communication and echolocation system. This waxy substance fills a cavity in the sperm whale’s head. And their head is mostly comprised of an expanded nose that serves as a highly calibrated sonar system. Sperm whales generate some of the loudest biological noises on record, communicate copiously using an array of complex vocalization styles, and have the largest brains on Earth.
They spend most of their time searching the ocean's depths for prey. They can stay submerged for over an hour, and dive deeper than 1,200 meters, far beyond sunlight’s reach, where they’re guided by sound.
The loudest noise recorded underwater is around 270 decibels. Sperm whale-generated sounds can reach 230. And they frequently fix their high-intensity echolocation clicks on squid. Some of the air they inhale through their blowhole is routed into their lungs, while the rest enters a complex, sound-producing system. There, air is funneled through lip-like appendages at the front of their heads. This generates a sound that travels backwards through their spermaceti organ, bounces off an air sac, then traverses another waxy organ, which amplifies and directs the sound. The click exits the sperm whale’s head a powerful, focused beam. It’s suspected that the returning vibrations are received by the whale’s lower jaw and directed into the ears. Then, their brain’s expanded auditory processing region analyzes the quality of the echoes to map their surroundings in the darkness.
With this mechanism, sperm whales can locate squid 300 meters away. Scientists think squid don’t hear these high-frequency clicks— even as they turn into rapid buzzes and creaks as the whale closes in. Sperm whales can eat more than a ton of squid every day. Their stomachs and feces are usually full of indigestible squid beaks, and their skin often scarred by squid tentacles.
When they're not hunting, however, sperm whales use an entirely different vocal repertoire. Mature males make clang noises, which scientists suspect play a role in mating. And most other sperm whales live in social family groups. Though their communication might get interrupted when predators are near or human-generated noises dominate, they generally chatter at length at the water’s surface. Sperm whales do this using patterned click sequences akin to Morse code, called codas, which are thought to function as social identity markers. Researchers have identified dozens of distinct types of codas, according to patterns in the numbers of clicks used and their rhythm and tempo. Some codas are more ubiquitous, while others vary greatly according to family groups and individuals. All families in a given region that consistently use some of the same characteristic coda patterns share a dialect and belong to the same vocal clan. Each sperm whale calf goes through a multi-year period of babbling, where they experiment with different sounds before becoming fluent in their clan’s coda dialect.
How and what exactly sperm whales communicate to each other is currently unknown, but there are indications that the information can be sophisticated. Biologists, roboticists, linguists, cryptographers, and artificial intelligence experts are collaborating to monitor and analyze sperm whale vocalizations. The aim is to finally decipher what they're saying.
