Basking shark skin reveals unique denticle structure for feeding adaptation

New research into the basking shark (Cetorhinus maximus) has uncovered fascinating details about its skin, particularly the unique arrangement of its dermal denticles. The study, conducted by a team from the City University of Hong Kong, was presented at the Society for Experimental Biology conference on July 9, 2026. Researchers believe these adaptations are critical for the shark's filter-feeding behavior.

Distinctive Structure of Basking Shark Skin

The basking shark is known for its massive size and slow swimming speed. Unlike other sharks, its dermal denticles are significantly larger and arranged in a pattern resembling 'paver blocks'. This unique configuration allows for greater elasticity in the skin, enabling the shark to open its mouth widely during feeding.

Mike Schindler, a Ph.D. student involved in the study, noted, "We only noticed that basking shark denticles were so special when we first investigated the bodies of beached specimens for the purpose of studying their oral filter structures." The arrangement of these denticles is different from the streamlined pattern found in other shark species, which enhances hydrodynamics.

Functionality of Denticles in Feeding

The research revealed that basking sharks possess denticles that can reach a diameter of approximately 0.5 millimeters, visible to the naked eye. In contrast, typical shark denticles are much smaller and require a microscope to be observed. Schindler explained, "What makes the basking shark's denticles particularly unique is their arrangement, since they are clumped together in groups to form what we're calling 'paver blocks.'"

This arrangement not only provides protection but also facilitates the extreme stretching required for their filter-feeding mechanism. The denticles are clustered in areas that undergo significant deformation, allowing the skin to accommodate the shark's feeding needs.

Evolutionary Insights from Fossil Records

By examining fossil records of extinct basking sharks, the research team has uncovered insights into the evolutionary history of these denticles. The findings suggest that the unique denticle arrangement may have developed in response to dietary changes over time. Schindler stated, "We suspect that, due to this species' slow swimming speed, denticles were released from a constraint, and the 'skin armor' instead took on a novel role in accommodating the stretching ability of the skin and repelling parasites between the folds."

These discoveries not only enhance our understanding of basking shark biology but also have potential applications in bioinspired materials. The unique properties of basking shark skin could inspire new designs in various fields.