The vast oceans are ruled by magnificent whales, who, despite being air-breathing mammals like humans, seem to exhibit remarkable intelligence. The sperm whale, in particular, boasts the largest brain of any animal on the planet, both on land and in water. While brain size alone does not equate to intelligence, sperm whales are known for their complex social interactions and behaviors throughout their long lives.

One intriguing aspect of sperm whale behavior that has baffled researchers for years is their method of communication, or apparent lack of it. However, recent collaborations and technological advancements have enabled scientists to explore sperm whale communication in new ways, revealing complexities previously unimagined.

Sperm whales are characterized by their gray color and large, block-shaped heads, which contain a waxy substance called spermaceti—this is also the source of their name and aids in sound focus. Between 1800 and 1987, sperm whales were heavily targeted by the whaling industry for spermaceti, leading to a dramatic decline in their populations, as it was widely used in candles, oil lamps, and lubricants.

While commercial whaling is no longer a significant threat, sperm whales are still classified as depleted under the Marine Mammal Protection Act and are listed on the Endangered Species Act due to their slow recovery.

In addition to having the largest brains of any species, sperm whales are also the largest toothed whales and one of the most widely distributed marine mammals, found across all the world's deep oceans—from the Arctic and Antarctic to the equator.

These whales can reach lengths of 40 to 50 feet (12 to 15 meters), making them longer than a semi-truck. They are capable of diving to depths of 6,500 feet (1,981 meters) and can remain submerged for over an hour while hunting approximately a ton of fish, sharks, and their favored prey, squid, each day.

Sperm whales typically travel in family groups called pods, consisting of around 15 to 20 females and their calves. These female pods often socialize, dive, and hunt together in warmer equatorial waters, engaging in communal care for their young.

In contrast, male sperm whales migrate to colder waters, often traveling alone or in small groups, returning to the equator primarily for mating. Their powerful tail flukes, measuring about 16 feet (4.8 meters) from tip to tip, enable them to swim at speeds of approximately 23 miles (37 km) per hour.

Despite the wealth of knowledge gained about sperm whales, their communication methods remain elusive. Unlike the melodious songs of humpback whales, sperm whales utilize clicking sounds that Lauren Sommer from NPR likens to “a blend of Morse code and popcorn popping.”

Biologist Shane Gero has dedicated years to understanding these clicks while studying sperm whales in the Caribbean as part of the Dominica Sperm Whale Project. Gero, a National Geographic Explorer and co-author of a recent study, observed vocal exchanges among sperm whales for an hour, noting that overlapping conversations are not considered impolite in their society.

Researchers have been recording these clicking exchanges for decades in hopes of identifying patterns. The fast-paced clicks produced by sperm whales are termed “codas,” which can consist of anywhere from 3 to 40 clicks each.

Between 2005 and 2018, the Dominica Sperm Whale Project documented a clan of 400 sperm whales in the Eastern Caribbean, utilizing underwater listening stations and acoustic tags to capture nearly 9,000 instances of codas from at least 60 individuals. Gero remarked on the project's advantages, stating, “We’ve known these sperm whales for so long,” allowing them to understand the social dynamics of the interactions.

Gero also leads the Cetacean Translation Initiative, known as Project CETI, which aims to decode whale communications. He expressed the importance of observing whales interact, noting that it enables researchers to discern what information may be exchanged.

Traditionally, scientists examined sperm whale codas in isolation, a labor-intensive process that can take hours to analyze just a few minutes of recordings. However, recent advances in technology and collaborative research have streamlined this analysis.

In a groundbreaking study published in Nature Communications, Gero and his colleagues at Project CETI and the Dominica Sperm Whale Project, along with Pratyusha Sharma, a Ph.D. student at MIT, re-evaluated nearly 9,000 codas. Sharma explained, “If you were to listen to the sounds of sperm whales, or even plot them, it could look like the whales just make the same sounds over and over again.”

For their research, the team developed a new analysis method called an “exchange plot,” utilizing sophisticated computer algorithms to detect patterns in the whale codas, suggesting that their communication may be more intricate than previously understood.

Instead of analyzing individual codas, the researchers examined how these clicks relate to one another, focusing on variables such as tempo, sound length, rhythm, and additional sounds that could alter a coda's meaning. Gero illustrated this concept by comparing it to how different intonations can change the meaning of the phrase “Oh my God!”

The analyses indicated that whales can modify the tempo of their clicks, in addition to varying the number of clicks in a coda. This adjustment is referred to as “rubato,” a musical term for altering tempo, and sometimes sperm whales will append an extra click at the end of a coda, termed “ornamentation.”

The researchers identified a total of 156 unique codas, each with distinct rubatos, rhythms, and tempos, marking the first instance of what scientists are calling a “sperm whale phonetic alphabet.”

The team also posits that sperm whales may exhibit duality of patterning, a concept where meaningless individual elements combine to convey more complex ideas. For instance, various sounds (syllables) can be combined to create words, which can in turn be arranged into sentences, forming more sophisticated communication.

However, while their research suggests that variations in sperm whale codas may carry multiple meanings, Sharma and her colleagues refrain from labeling them as sentences. She cautioned, “Caution should always be taken when comparing non-human to human behavior, including comparing animal communication systems to human language.”

Moreover, despite the findings indicating the complexity of sperm whale codas, the exact meanings remain largely unknown, highlighting the need for further investigation before making human comparisons.

As co-author David Gruber, a biology professor at the City University of New York and a National Geographic Explorer, stated, “It’s an incredibly important first step in understanding the basic building blocks of the sperm whale communication system.”

Looking ahead, researchers aim to utilize the newly identified sperm whale phonetic alphabet to explore how these components interact and possibly decipher their meanings. Sharma mentioned that, “Once you have this combinatorial basis, it allows you to take a finite set of symbols and compose them to create an infinite number of symbols by following a set of rules.”

Future studies may involve correlating specific codas with particular behaviors, such as a whale asking a pod-mate to watch its young while it hunts. While it may not lead to precise word-for-word translations, it could provide insights into the general meanings of certain codas.

A deeper understanding of sperm whale communication could significantly aid in their conservation efforts. Although commercial whaling is prohibited, human-induced threats—such as climate change, pollution, ship collisions, entanglement in fishing gear, and increased ocean noise—continue to jeopardize sperm whales.

If experts could comprehend what sperm whales are conveying, it would enhance conservation strategies. Additionally, researchers hope that increased awareness of sperm whale communication could generate public interest, as meaningful change often occurs when individuals are invested in a cause.

In conclusion, while more research is necessary, the potential to understand sperm whale communication is thrilling for many reasons. The prospect that people may become more engaged in sperm whale conservation due to the revelation of their language is promising, though it is unfortunate that such a revelation is needed to inspire action.

Furthermore, the quest for intelligent life beyond Earth has shifted focus back to our own planet. While searching the universe for intelligent beings, we are uncovering an array of intelligent life forms that have long been overlooked, including elephants, octopuses, and, of course, sperm whales. The implications of communicating with these creatures are profound, and understanding animal communication could better prepare us for the possibility of extraterrestrial contact in the future.

This article was originally published in the author’s free newsletter, Curious Adventure. It was edited and republished on Medium with her consent.

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