New research suggests great white sharks may be able to lighten or darken their skin—possibly giving these already formidable predators another advantage when hunting.
THE BIG IDEA
Great white sharks are known for their iconic appearance; light grey on top with a white underbelly. This coloration is an adaptation that camouflages these apex predators from both above and below.
But scientists have observed something far more surprising.
The same great white shark may look lighter or darker—not over weeks or months, but within the very same day.
As recently as 2022, scientists began investigating changes in great white shark coloration. Rather than differences between individual sharks, researchers observed individual sharks appearing to change color from day to day—and even hour to hour.
Photo: Steve Hinczynski
The Discovery: A Shark That Changed Color in Hours
In 2022, scientists Gibbs Kuguruu and Ryan Johnson performed the first experiment on great white shark skin pigmentation. They were the first scientists to notice the same great white shark being a different color on the same day.
From Hammerhead Tans to Great White Color Changes
A 1996 study on hammerhead sharks found that scalloped hammerhead sharks tan when they spend more time in the shallow waters. This study focused on color pigmentation changes over a long period of time, more than a week. They concluded that hammerhead sharks could tan if they spent abnormally high amounts of time in the shallow waters. However, Kuguruu and Johnson sought out to prove great white sharks didn’t just tan, they could change their coloration in the same day.
How Do You Prove a Shark Changed Color?
Kuguruu and Johnson’s team photographed white sharks leaping out of water and compared their skin to a board with different colors. Using identifying factors such as scars or abscesses, their team was able to identify a change of color on the same day in the same sharks.
Researchers identified individual sharks by scars and other markings—and found the same shark could appear lighter and darker on the same day.
Photo: Steve Hinczynski
The Secret May Be Inside Their Skin Cells
Then the researchers looked at the molecular changes in shark skin cells. Scientists performed experiments using hormones on great white shark melanocytes (skin cells). They found these cells reacted to both adrenaline and MSH (a hormone that controls skin cells). The reaction of the skin cells both directly impacted the shade of grey of the shark skin.
WHAT THE LAB FOUND
- Great white shark skin contains pigment-producing cells called melanocytes
- Researchers exposed those cells to adrenaline and MSH
- The cells responded by changing pigmentation
- Those changes affected the shade of grey seen in the shark’s skin
The leads of the research team are Ryan Johnson and Gibbs Kuguruu. Ryan Johnson is a shark biologist at the Blue Wilderness Research Unit in South Africa. Gibbs Kuguruu is a shark scientist at Wageningen University. While their findings have not yet been validated by other scientists this hypothesis is corroborated by Dr. Elliot and Dr. Burkhardt’s research.
Then Scientists Found Sharks That Were Almost Black
Why Were These Great Whites So Dark?
Dr. Riley Elliot and Dr. Kori Burkhardt were featured on 2026’s Shark Week: Chum Island: Catching a Killer. On the show, the duo followed the great white sharks who were hunting sperm whales along the coast of Australia and New Zealand. They noted how the great white sharks were almost pitch black, a stark contrast to the light grey sharks they are accustomed to. Even local surfers were getting caught off guard by the camouflaged white sharks as they were not used to their dark pigmentation. This unfortunately led to an increase in shark attacks amongst surfers. So, Dr. Elliot and Dr. Burkhardt set out to see why these great white sharks were so dark.
A Great White Built for the Darkness?
The transient great whites were reportedly almost pitch black—a stark contrast to the lighter grey sharks normally seen in the area.
[PHOTO: Very dark great white shark / comparison between dark and lighter white sharks] If you can obtain images of a dark transient shark and a typical lighter shark, I’d actually put them side by side. That would probably be the most effective visual on the entire page.
After observing the great white sharks hunting in the Australian coastal waters. Dr. Riley hypothesized the great white shark pigmentation was an adaptation to hunt sperm whales. These scientists believe the transient white sharks had a darker pigment to blend into the darker waters near New Zealand.
Beyond the Research: A Conversation With Dr. Riley Elliot
Dr. Elliot was kind enough to give us an opportunity to interview him. During our interview, Dr. Elliot shared more about his ideas of shark conservation. He explained how he does these three things to help conserve sharks.
Three Ways Elliot Says We Can Help Sharks
Dr. Elliot was kind enough to give us an opportunity to interview him. During our interview, Dr. Elliot shared more about his ideas of shark conservation. He explained how he does these three things to help conserve sharks.
1. Put sharks in the spotlight
Participate in Shark Week. Despite controversy surrounding the programming, Dr. Elliot believes its enormous audience can help generate funding and interest in shark conservation.
2. Follow sharks wherever they go
Tagging great whites allows researchers to track their movements and learn more about their behavior.
3. Make living sharks valuable
Dr. Elliot supports responsible great white cage diving and argues that the economic value generated by shark tourism has helped create incentives to protect sharks.
“[Cage diving] single-handedly kept great white sharks alive.” — Dr. Riley Elliot
Because that’s a provocative statement, I’d keep the following explanation making clear that this is Elliot’s view and explaining his reasoning rather than presenting it as an established scientific conclusion.
Photo: Dr Riley Eliot cage diving with a great white shark in New Zealand. The Denizen, Amber Jones, Dec 2024
From Fear of Sharks to Fighting for Them
What makes someone dedicate their life to sharks? For Dr. Elliot, it actually began with fear.
He was afraid of sharks.
His fear initially drove his interest in diving with sharks. Those encounters eventually developed into an interest in shark conservation.
Big animals made him feel small.
Part of Elliot’s fascination comes from encountering animals that dwarf us—including basking sharks and whale sharks.
Sometimes protecting sharks begins with simply seeing them differently.
The More We Learn, the More We Have to Lose
Great white sharks have been studied for decades, yet researchers are still uncovering surprising aspects of their biology and behavior. The possibility that they can rapidly alter their pigmentation is another reminder of how much remains to be discovered. Scientists like Dr. Riley, Dr. Burkhardt, and Kuguru are vital to the expansion of knowledge on sharks. However, it is important to not lose sight of the danger sharks are in. Factors like shark finning, over-fishing, and nets in the water all contribute to the decreasing shark population.
Research Is Only Part of Shark Conservation
There are many organizations and activists fighting to conserve great white sharks. You can support shark conservation through sponsoring a shark through Dr. Elliot, diving with sharks with Dr. Burkhardt, or supporting Shark Angels mentorship initiative.
SPONSOR. DIVE. BECOME A SHARK ANGEL.
“As a Shark Angels intern, I’ve seen firsthand how education, communication and advocacy can help people understand why sharks matter—and how they can help protect them.”– Ailani Duncan