The remarkable behaviour of the sperm whale

In the annals of natural history, parallels between human societies and those of other species often go unnoticed. However, recent revelations from our ocean have unveiled interesting parallels between human societies and sperm whale (Physeter macrocephalus) clans. But what does the history of humanity have to do with the majestic sperm whales, you might ask? As it turns out, quite a lot.

“The facts about sperm whales rival in some ways the extreme capacities and behaviours that until recently we thought were uniquely human,” Professor Hal Whitehead of Dalhousie University, Canada, in a press release.  “The sperm whale, for example, has the greatest geographical division between the sexes: The females live in tropical and subtropical waters all around the world, while the mature males, reaching three times the mass of the females, are mostly found in or near the Arctic or Antarctic. […] The females and young males babysit the infants while mothers make dives of 40 minutes to depths of up to a kilometre to catch the deep-water squid, which is their staple food. Females also suckle each other’s infants, and families defend themselves against predators communally.”

Among the largest predators on Earth, sperm whales are characterized by their enormous heads and distinctive square-shaped flukes. Sperm whales play a crucial role in marine ecosystems, and have faced centuries of exploitation due to their valuable spermaceti oil, and meat, resulting in significant declines in their populations.

With the cessation of whaling, researchers have turned their attention to understanding the social dynamics of these enigmatic creatures. With brains larger than any other animal, sperm whales exhibit remarkable intelligence and social behaviours, living in matrilineal units led by older females. These deep-sea dwellers form intricate clans, centred around ten or so females and their offspring. Together, they navigate the ocean’s depths, forging bonds that echo the communal ties of human communities.

Researchers observed mesmerizing displays of social cohesion, as females and young formed tight-knit alliances, protecting each other from ocean predators.

Whitehead and other scientists were studying sperm whale vocalizations off the Galápagos Islands, when they discovered a compelling pattern. The codas, organized into two distinct clans — nick-named ‘Regular’ and ‘Plus-one’ — marked social divisions. Astonishingly, social units only formed groups with other units from their own clan, indicating a cultural distinction that echoed human ethno-linguistic groups. In fact, they found dialects passed down from one generation to the next!

In the Pacific Ocean, researchers identified seven distinct clans, each with its own unique characteristics and range. The ‘Short’ clan exhibit a remarkable cosmopolitanism, spanning vast distances across the Pacific—from Japan to Chile, covering an astonishing 10,000 kilometres. This extensive range implies a level of connectivity and adaptability that allows them to thrive in diverse oceanic environments. The ‘Plus-one’ clan demonstrate a more localized existence, with their presence confined to specific regions, such as the Galápagos Islands and mainland Ecuador.

Whales’ use symbolic markers which surpass mere communication; it reflects a level of cultural sophistication previously seen in non-human species. Much like human societies, their clans use dialect variations and cultural expressions to delineate their identities and forge bonds within their social groups. Through subtle nuances in their vocalizations and behavioural patterns,  the use of these symbolic markers among sperm whale clans underscores the depth of their social organization and the richness of their collective heritage.

Yet, despite numerous discoveries, mysteries abound. The emergence of new clans, such as the ‘EC3,’ raises questions about cultural exchange within sperm whale communities.

Encountered sporadically amidst the waters off Martinique and St Lucia, in the Caribbean, the EC3 clan embodies a singular anomaly within the framework of sperm whale society. Its vocal repertoire, characterized by codas containing 9–11 regularly spaced clicks, sets it apart from the established dialects of other clans, hinting at a divergent cultural heritage and social identity. Is the EC3 clan a distinct entity, with its own unique lineage and traditions, or does it represent a vocal anomaly within the framework of established clans?

“The parallels between these two unrelated species living in quite different environments suggest common environmental drivers for large-scale social structures,” says Whitehead.

Marine animals, particularly cetaceans like killer whales and dolphins, as well as certain fish species, exhibit cultural behaviours similar to those observed in humans and sperm whales. Killer whales, for instance, are known for distinct hunting strategies, vocalizations, and dietary preferences that vary among different populations or ecotypes.

Similarly, dolphins display variations in vocalizations, feeding behaviours, and social structures across different regions, indicating the presence of cultural differences among populations. And one cannot mention marine ‘language’ without bringing up the elaborate songs of humpback whales, and how they evolve over time and vary between populations, suggesting learned behaviours passed down through social learning. Even among fish species, evidence of cultural behaviours such as site fidelity and learned habitat selection has been documented, challenging traditional notions of ‘culture’ as a uniquely human phenomenon. These observations underscore the complexity of social behaviours and the presence of cultural traditions across diverse marine species.

“It seems exceedingly unlikely that sperm whale clans have more than a small fraction of the richness and complexity that distinguish human groups,”: says Whitehead. “But there are some broad-scale similarities that have few parallels elsewhere.”

In the end, the story of sperm whale clans is more than a mere scientific inquiry—it is a testament to the enduring power of culture, uniting all creatures on our planet.