Sperm Whales Finally Headbutted on Camera—and That Changes Everything

The Anatomy Was Obvious. The Behavior Wasn’t.

For two centuries, a question about sperm whales sat unresolved. Their heads occupy roughly a third of their body length and are built around two oil-filled chambers separated by walls of tough connective tissue, sitting in front of a fused, reinforced block of neck vertebrae and cushioned by unusually thick skin. Marine biologists noticed that this arrangement resembled a piece of equipment rather than a sensory organ. Something built to absorb and deliver an impact. What nobody had actually filmed was a sperm whale using it that way against another sperm whale.

That has now changed. A team led by Alec Burslem, who carried out the work at the University of St Andrews and is now based at the University of Hawaii, published drone footage documenting sperm whales colliding head-on, striking one another with the front of their skulls. The study appeared in Marine Mammal Science in March 2026, with the University of the Azores and the Balearic Islands-based NGO Asociación Tursiops as collaborators.

What the drones caught was straightforward. Between 2020 and 2022, the team gathered footage off the Azores and the Balearic Islands using drones positioned directly overhead, an angle boat-based or shore-based observation can’t provide cleanly. The drones documented three clear cases of one whale approaching another head-on and striking it with its own head. In one instance, the impacting whale pushed the other along for a short distance afterward.

Burslem called the observation “really exciting.” The behavior had long been hypothesized, he said, but never documented and described systematically. The overhead drone perspective, he added, is one of several ways the technology is changing what can be captured in wild whale behavior.

A Body Built for Battle

The hypothesis behind the new footage is not recent. In 2002, David Carrier, Stephen Deban, and Jason Otterstrom published a paper in the Journal of Experimental Biology titled “The face that sank the Essex.” They argued that the whale’s spermaceti organ—the oil-filled structure that gives the animal its name—has all the hallmarks of a weapon rather than a purely sensory adaptation.

They pointed to the lower chamber, known as the junk, reinforced with transverse partitions of connective tissue. To the fused cervical vertebrae just behind it, which would transmit force rather than absorb it in the neck. And to scarring concentrated on the underside of large males’ heads, consistent with repeated impacts. Their argument was that the structure evolved through sexual selection, in male-on-male contests, much like antlers or tusks in other species.

Their case drew on centuries of whaling accounts. The whaleship Essex, struck twice and sunk near the Galápagos in 1820, provided the incident that inspired Herman Melville’s Moby-Dick. The whaleship Ann Alexander was rammed and sunk in the South Pacific on August 20, 1851, by a whale its own crew had wounded earlier that day. The bark Kathleen was sunk roughly 1,000 miles off Brazil in 1902, an attack its captain, Thomas H. Jenkins, later described in his own written account.

The 2002 paper built a plausible anatomical weapon. It took drone footage nearly two and a half decades later to show it, however rarely, actually being used on another whale.

The Detail That Complicates Everything

Here is where the new footage complicates the older theory more than it confirms it. The 2002 hypothesis was specifically about large adult males competing for mates—the animals with the biggest, most heavily scarred heads. The whales caught headbutting in the Azores and Balearic Islands footage were sub-adults, younger than the mature bulls the sexual-selection theory was built around.

That leaves the researchers with a documented behavior and an incomplete explanation for it. Dominance testing among younger, not-yet-breeding males is one possibility. Something closer to rough play, of the kind seen in juveniles of other social species, is another. There’s also a genuine puzzle in why any sperm whale would risk this at all. Researchers studying the species have noted that using the head as a weapon habitually is a strange thing for evolution to favor, given how close the spermaceti organ sits to structures the whale depends on for echolocation and social communication. Damage there isn’t a small cost.

The front of a sperm whale’s head houses sound-producing structures in its nasal passages that the animal relies on for echolocation and, in some contexts, communication with other whales. Deliberately slamming that region into another animal is a strange trait for evolution to preserve if the cost is a meaningful chance of damaging the very apparatus the whale needs to navigate and hunt in deep, dark water. That tension—a body part central to survival being used as a weapon against the same species—is part of why researchers have been cautious about assuming the anatomical case settles the behavioral one.

The Limits of What We Can See

The current paper doesn’t resolve any of this. Three documented collisions, gathered opportunistically across three years of fieldwork at two sites, is a start. It’s too small a sample to support a firm conclusion about why the behavior exists or how common it is. The researchers have said as much themselves, framing the result as evidence that more overhead drone monitoring, sustained across breeding grounds and over longer stretches, is needed before the function of the behavior can be pinned down with any confidence.

What has changed is narrower and more concrete. A piece of anatomy that spent two hundred years looking like a weapon with no witnessed use finally has one. Whether that weapon is mainly used by mature bulls fighting over mates, as the 2002 hypothesis proposed, or by younger whales testing something else entirely, is now a question with a handful of real footage attached to it, where before there was none.

The broader lesson extends beyond sperm whales. Boat-based fieldwork has always struggled to capture clean observations of surface behavior from the angles that matter most. Overhead drone footage, still an emerging tool in marine biology, is opening windows into behaviors that were previously invisible or inferred only from scars and speculation. The three collisions captured between 2020 and 2022 are rare precisely because the opportunity to film them was rare, not because the behavior is necessarily rare.

Two centuries of anatomical reasoning pointed toward a conclusion. It took aerial drones and careful fieldwork to reach it. The surprising detail—the age of the whales caught fighting—suggests the story may be more complicated than anyone expected. That complication is where the science goes next.