A Bold Shift in Shark Science: What We Still Don’t Know About Great Whites
For years, our picture of the ocean’s most dreaded apex predator has been built on a partial, often surface-level view. Australian researchers now claim that the tiny, unseen inhabitants inside great white sharks could upend everything we thought we understood about these iconic predators.
A groundbreaking world-first study identifies a surprising gap in marine science: despite decades of focused study on great whites, scientists know next to nothing about the microscopic hitchhikers that live inside them. Those minuscule organisms—primarily tapeworms and copepods—may influence shark behavior, energy use, stress responses, and even how we interpret encounters between sharks and humans.
Charles Sturt University researchers report that at least 116 parasites have been found in great white sharks, but how these organisms affect shark health, decision-making, or behavior remains largely unexplored. This finding has sent tremors through the marine science community, exposing substantial blind spots that span oceans.
“We have almost no understanding of how these organisms influence shark health, energy use, decision-making, behavior, susceptibility to stress, or even patterns we assume to be ‘attacks.’ In short, we’re only seeing the surface when we study sharks,” explains Professor Shokoofeh Shamsi, a veterinary parasitology expert at Charles Sturt University.
The study, published in the International Journal for Parasitology: Parasites and Wildlife, is the most comprehensive review to date. It draws on global scientific literature and specimens from major museums, including the Smithsonian and Australia’s Helminthological Collection.
What’s striking is the sheer scope of what remains unknown. Professor Shamsi and Associate Professor Diane Barton found that almost all prior work on shark parasites is descriptive—researchers have identified what exists but not what it does.
This global mapping reveals enormous data gaps, with vast regions lacking parasite information even though great white sharks roam worldwide, from the United States and South Africa to New Zealand and Australia, Shamsi notes.
The implications are profound. In many other species, parasites and microbes can shape energy levels, stress responses, feeding choices, and decision-making. In great whites, these invisible forces have hardly been studied at all.
“Perhaps the most exciting discoveries about great white sharks lie in what we’ve never studied—their parasites and microbiome,” says Shamsi. “By examining these internal communities, we may uncover quiet drivers of behavior, resilience, and ecological role.”
Although there is no evidence linking parasites to direct shark-human attacks, the researchers argue it’s vital to consider how these internal factors might influence shark behavior in ways scientists have yet to measure.
“Great white sharks are remarkable, global icons, yet they are not immune to the microscopic world. The parasites, microbes, and other symbionts living inside them remain largely unknown,” Shamsi adds.
The study also prompts questions about how human activity affects sharks in previously unimagined ways. Pesticides, pollutants, and land-based pathogens wash into coastal waters, traverse food webs, and ultimately reach apex predators. Parasites can act as sentinels, signaling when ecosystems are stressed or breaking down.
“Human actions on land directly influence marine predator health, which is why inland regional researchers play a national role in marine conservation, even when they’re miles away from the sea,” Shamsi emphasizes.
That inland vantage point can be advantageous: what happens on land travels through waterways and food webs to shape the health of giants like great whites. Our work illuminates those hidden links.
Barton highlights the crucial role of museum collections in enabling these discoveries. Preserving irreplaceable biological material allows researchers to revisit specimens with new technologies and uncover insights that were impossible to detect when the samples were first collected.
Perhaps most telling is the broader scientific community’s awareness of this research gap. A major recent publication, White Sharks Global: Proceedings and Recent Advances in White Shark Ecology and Conservation, contains no chapters on parasites or microbiomes. The absence underscores how large this blind spot is and why this review serves as a timely corrective—an initial step toward understanding the unseen biological layers that could shape health, behavior, and long-term survival.
The researchers caution that parasites aren’t villains but storytellers. They can reveal pollution levels, prey stress, and broader pressures on marine ecosystems. If we ignore them, conservation efforts remain incomplete.
“Parasites provide early warnings about ecosystem stress, pollution, and shifting food webs,” Shamsi notes. “Healthy oceans depend on recognizing the small things—the hidden architecture of parasites and microbes.”
The study poses a provocative question that challenges decades of shark research: could aspects of a shark’s behavior, including unusual interactions with humans, be influenced by factors we’ve never measured? While we don’t yet know, the researchers say that’s precisely why this work matters.
As human activity in the world’s oceans continues at a rapid pace, understanding these invisible biological forces grows increasingly urgent. The path to clearer answers may lie not in studying sharks alone but in finally studying what lies inside them.
