Sperm Whale Headbutting: First Scientific Documentation Validates Historic Accounts

Scientists have successfully documented and filmed instances of sperm whales engaging in headbutting behavior, marking the first formal scientific description and video evidence of this activity.

Utilizing drone technology during fieldwork in the Azores and Balearic islands between 2020 and 2022, researchers observed sub-adult whales striking each other with their heads. This documentation provides scientific validation for 19th-century historical accounts of sperm whales using their heads to impact objects, including ships, which notably inspired Herman Melville's novel "Moby Dick." The specific reasons for this behavior are not yet fully understood and remain an area of ongoing research.

First Scientific Documentation

The study, published in Marine Mammal Science, represents the first time sperm whale headbutting has been captured on video and observed in-water. Research teams from the University of St Andrews, Tursiops Association, and University of the Azores collaborated on the project.

Dr. Alec Burslem, lead author from the University of St Andrews, highlighted the significance of systematically documenting this behavior, which had been hypothesized for centuries but lacked direct evidence. Marine biologist Robert Harcourt, not involved in the study, noted that such fleeting behaviors are challenging to observe without modern drone technology.

Echoes from History: Validating 19th-Century Tales

Historical records, particularly from 19th-century open-boat whaling, describe sperm whales using their heads to push and strike objects. A prominent incident cited is the 1820 sinking of the whaling ship Essex, a 27-meter vessel reportedly struck twice by a large bull sperm whale off the Galapagos. First mate Owen Chase documented the whale's forceful impact.

Other ships, including the Ann Alexander and Kathleen, also reported similar sinkings in the same century. The current observations confirm that sperm whales can strike with considerable force using their heads, lending credence to these historical accounts.

Unveiling the Behavior: Drone Observations

Drone footage captured various instances of headbutting:

• Balearic archipelago (2022): Two juvenile male whales were observed interacting near a female. One male diverted its course and made contact with the female, who subsequently departed while the two males continued their interaction.
• Azores archipelago: One video depicted whales of unknown gender colliding head-to-head, accompanied by patterned clicking sounds. Another video showed two suspected male whales striking each other in the head or body with varying force.

The observations indicated that sub-adult whales were involved in these activities, contrasting with some earlier hypotheses that suggested large adult males were the primary participants in such forceful interactions.

Hypotheses and Unanswered Questions

The specific purpose of sperm whale headbutting is not yet fully understood due to insufficient data. Researchers have put forward several hypotheses:

• "Rough Play": Some head-on interactions might represent a form of "rough play," occurring alongside other common social behaviors like rolling and jaw opening. Professor Harcourt supported this idea, noting it is common in immature social mammals.
• Group Cohesion and Dynamics: The study's authors speculate that headbutting among young males could impact group cohesion, potentially contributing to their departure from matriarch-led groups as they transition to adulthood.
• Physical Contests/Male Competition: The behavior may have evolved from physical contests, potentially linked to male-male competition. However, some theories previously suggested that using the head as a weapon might be unlikely to be favored by evolution due to the risk of damaging structures vital for echolocation and social communication.

Regarding potential injury, Professor Harcourt indicated that the forces observed were significant but likely not severely damaging unless applied excessively. He also noted that while male whales of many species ram each other during competition for females, this specific context was not evident in the current observations.

The sperm whale's brain, the largest of any living creature, is located far back in the skull, protected by a significant amount of soft tissue and a spermaceti organ filled with oil, which accounts for up to 40% of its body length. Dr. Burslem confirmed that a sperm whale could create a hole in a wooden ship.

Implications and Future Research

The increasing use of drone technology in wildlife biology is transforming the study of marine life, offering unique overhead perspectives that enable the discovery and documentation of previously unseen behaviors. Researchers anticipate that drones will provide more opportunities to observe this and other near-surface activities.

Further research on headbutting in adult whales is necessary to fully understand the behavior, especially regarding its potential role in sexual competition if observed between sexually mature males in the presence of females. Dr. Burslem has expressed interest in receiving additional footage from others who may have documented similar behavior.