Shark Scars Reveal Hidden Lives and Mating Secrets
Researchers Decode Wounds to Unlock Great White Mysteries
The ocean’s depths conceal much about sharks, but a new study reveals their stories are etched onto their very bodies. Scientists are learning to read the scars and wounds of great white sharks, gaining insights into their battles, breeding habits, and encounters with the human world.
Decoding the Marks of the Deep
A team led by Scot Anderson from the California White Shark Project has developed a system for categorizing shark injuries. The scars and wounds seen on the sharks tell us about their interactions with each other, their environment, their prey and humans,”
explains Anderson. This approach transforms each mark into a clue about a shark’s life.
One common culprit behind distinctive circular scars is the cookiecutter shark (Isistius brasiliensis). These smaller sharks take neat, plug-like bites, often during the great whites’ offshore migrations. Cookiecutter wounds can tell us the white sharks get these marks during the ‘offshore phase’ off their migration as that is when they overlap habitat with cookiecutter sharks,”
Anderson notes.
Beyond cookiecutter bites, scars can indicate boat collisions, territorial disputes, or even mating encounters. According to the International Shark Attack File, there were 74 unprovoked shark attacks worldwide in 2023, highlighting the potential for interaction—and injury—between sharks and humans. Florida Museum
Evidence of Mating Rituals
Intriguingly, some scars suggest how great whites reproduce. Females may bear light impressions
from bites sustained during mating, as male sharks often bite to maintain their grip during copulation. These hold bites
are typically healed when observed, suggesting mating occurs offshore, offering a vital clue to understanding this elusive process.
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The research team shared a video of a 16ft female great white shark sporting a perfect circular scar on her head—a clear sign of a cookiecutter shark encounter. The study proposes a systematic classification system
to help scientists accurately identify the origins of various injuries, from parallel cuts caused by boat propellers to rope burns from entanglement in fishing gear.
Ultimately, this work emphasizes that each scar tells a story. It’s another puzzle piece that tells a story of what these white sharks experience,”
Anderson concludes, offering a new window into the lives of these magnificent predators.
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