Great white sharks are one of the most iconic and feared predators in the ocean. Their massive size, torpedo-like shape, and rows of serrated teeth make them perfectly suited for hunting seals, sea lions, fish, and even other sharks. But despite their fame and fearsome reputation, there remains much we don’t know about these ancient beasts of the deep.
One of the most debated questions about great white sharks is what color they really are. Most reference photos and footage shows great whites with a grey dorsal surface and white underside. This counter-shading camouflage helps break up their outline when viewed from above or below. But some divers and photographers swear that great whites can appear blue or even black in certain lighting conditions.
So which is it – are great white sharks grey like conventional wisdom states, or do they really exhibit an elusive blue hue? In this article, we’ll dive into the available evidence to solve the mystery of the great white shark’s true colors.
The Case for Grey
Most scientific sources describe great white sharks as being grey on top and white below. This is clearly visible in photos of great whites taken near the ocean’s surface in full sunlight. Under these conditions, their counter-shaded pattern stands out distinctly.
Researchers who have observed great whites underwater also consistently characterize them as grey. In neutral light conditions, nothing about their appearance suggests they are blue.
The grey color comes from the skin itself, which contains pigment cells called chromatophores. By contracting and expanding these cells, sharks can dynamically adjust their skin’s lightness or darkness to better match their surroundings – a form of adaptive camouflage.
When a great white is hunting near the bright surface, the cells contract to make the dorsal surface appear lighter grey. This counters the sunlight from above and matches the lighter tones of the sea foam and sky. When swimming in the dim depths, the cells expand to darken the sharks’ grey topside, masking their silhouette when viewed from below.
Clues of Blue
Yet despite the prevalent grey color reported in the scientific literature, many divers adamantly claim that great white sharks can look distinctly blue underwater. Some photographers have even captured rare images showing great whites with an undeniable blue cast.
Most sightings of blue great whites seem to occur when the sharks are deeper, in greenish blue ocean waters. Instead of neutral grey, the sharks exhibit a subtle blue tint that closely matches the surrounding water color.
Amazingly, the blue is not purely an optical illusion caused by the environment. Careful analysis of underwater photographs reveals that the blue regions correspond directly to the sharks’ skin, while the gills and mouths remain white. The color change apparently comes from physiological changes in the sharks themselves.
Some researchers now believe great whites have an additional adaptive superpower – the ability to actively shift their skin’s hues to act as ultra-effective camouflage in changing conditions.
The Skin of a Chameleon
New studies reveal that great white skin contains specialized color-changing cells called iridophores, similar to chameleon skin. By adjusting these cells, great whites may be able to dynamically match both the brightness and hue of their environment for true adaptive coloration.
Iridophores contain stacks of reflecting platelets that can selectively reinforce specific wavelengths of light. By tuning the distance between plates, great whites could conceivably produce iridescent blues, greens, and greys depending on the predominant water color.
This discovery explains how the same sharks can appear grey at times and richly blue at others. The iridophores provide exceptional camouflage across depths and conditions that static grey skin alone cannot match.
A Combination of Factors
Of course, physics plays a role as well in the sharks’ varying appearances. Water absorbs long wavelength red light first, leaving mostly blue and green at depth. White objects can take on a blue caste underwater simply due to the remaining light spectrum.
The interplay between the sharks’ dynamic skin and the aquatic light field makes their true color complex to pin down. But the evidence now suggests great white sharks possess highly tunable skin capable of an array of grey and blue hues depending on the circumstances.
Conclusion
So are great white sharks blue or grey? The best answer is that they can appear both blue AND grey!
While usually neutral grey near the surface, great whites seem capable of shifting to blue hues when at depth. This is accomplished using special color-changing cells in their skin that provide exceptional camouflage and may help make great whites such successful hunters.
The sharks’ elusive blue coloration could be the secret to how these massive predators go unseen until the final moments of their explosive attacks. So despite their fearsome reputation, great whites have evolved remarkable subtleties that keep their prey continually guessing about their presence in the oceans around us.
| Environment | Observed Color | Mechanism |
|---|---|---|
| Near surface in sunlight | Grey | Chromatophore contraction |
| In deeper, blue-green water | Blue | Iridophore plate spacing |
