With 12 colour receptors, the mantis shrimp seems visually unmatched. But studies reveal that their visual system likely isn’t as rich as we previously believed.
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Mantis shrimp (order Stomatopoda), or stomatopods, have become living legends in popular science: they’re frequently described as having the most complex eyes in the animal kingdom. With this visual system, they can see colors we can’t even conceive of.
It’s a scientific claim that seems almost too interesting to be true: a small, iridescent crustacean that glides through coral reefs is somehow able to perceive a kaleidoscope of colors far beyond human comprehension.
But as is often the case in biology, the truth behind the claim isn’t as cut and dry as popular culture allows for — and is also more interesting. Yes, mantis shrimp possess an extraordinarily sophisticated visual system. Yes, they can detect forms of light that are entirely invisible to us. But whether they experience a richer world of color is a very different question.
To understand what’s really going on, we need to look closely at how their eyes work, how scientists uncovered their abilities and, most importantly, how their visual system differs from our own.
In a renowned 1999 study published in Nature, researchers Justin Marshall and Johannes Oberwinkler provided some of the first compelling experimental evidence of just how unusual these mantis shrimps’ eyes really are.
In that study, researchers examined the photoreceptors (light-sensitive cells) inside the eyes of a swollen-claw mantis shrimp (Neogonodactylus oerstedii). Using electrophysiological techniques, the researchers measured how the individual photoreceptor cells responded to different wavelengths of light. In turn, the researchers could map out the spectral sensitivities of the shrimp’s visual system with precision.
Instead of the three types of color receptors found in humans — sensitive to red, green and blue wavelengths — the researchers found that mantis shrimp possess at least 12 distinct classes of photoreceptors. What’s even more remarkable, however, is that several of these are tuned to wavelengths in the ultraviolet range, which lies entirely outside human perception.
At first glance, this seems to suggest an almost unimaginably rich visual experience. After all, more photoreceptors should mean more colors, right? But that assumption is precisely where the matter becomes complicated.
In a 2014 study published in Science, researchers challenged the intuitive idea that having more photoreceptors automatically translates into better or richer color vision.
In humans and many other animals, color perception depends on how visual signals are processed, rather than just the number of photoreceptors a species has. As opposed to having our cones work in isolation, our brains compare their outputs to compute differences between them. This comparative processing is what enables us to discriminate between extremely fine gradations in color, far more than what our having merely three receptors would suggest.
The 2014 study took a behavioral approach to understanding vision in the mantis shrimp species Haptosquilla trispinosa. Instead of focusing solely on their anatomy, the authors trained the mantis shrimp to associate specific colors by means of food rewards. Then, they tested how well the shrimp could distinguish between similar hues.
Surprisingly, they found that the mantis shrimp were actually relatively poor at discriminating between closely related colors. In some cases, they performed worse than animals with far fewer photoreceptor types.
This forced the researchers to rethink their working model of color vision for mantis shrimp. As such, in a follow-up 2014 study published in i-Perception, the researchers put forward a new hypothesis: instead of comparing signals across receptors, mantis shrimp likely use a more direct system.
In this system, each photoreceptor acts almost like an individual channel, responding to a narrow range of wavelengths. So, rather than blending information across channels as we would, mantis shrimps’ visual systems may simply “read out” which receptor is activated most strongly, as though their eyes are selecting from a set of predefined labels.
This suggests that mantis shrimp aren’t necessarily experiencing a more exquisite spectrum of colors than we are, unlike the popular narrative suggests. Instead, it seems they’re using a system optimized for speed and efficiency, as opposed to one that prioritizes fine discrimination.
Since mantis shrimp almost certainly aren’t seeing a more detailed rainbow than we are, many may still wonder what the point is of having such an elaborate visual system. The answer to this relates to the specific ecological demands that their environment poses.
More specifically, mantis shrimp inhabit visually complex and fast-moving ecosystems, namely coral reefs. Here, light conditions will change rapidly depending on the water’s depth and turbidity, as well as due to shifting angles of sunlight. In an environment like this, the ability to quickly and reliably identify visual signals would be more valuable than distinguishing between subtle differences in similar colors.
Their visual system appears to be perfectly tailored for this exact task. Because each photoreceptor is tuned to a specific range of wavelengths, mantis shrimp can quickly categorize incoming light without having to make any computationally intensive comparisons. This would enable near-instantaneous recognition of biologically relevant signals, which would be a crucial advantage when detecting prey, avoiding predators or communicating with other shrimp.
Coral Reef and Tropical Fish in Sunlight.
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Communication, in particular, is where their visual abilities prove especially intriguing. Mantis shrimp are known for their vivid body patterns; many of them even reflect UV light or exhibit properties invisible to human eyes. By evolving sensitivity to these wavelengths, this would enable the exchange of signals that are totally hidden to other species, forming a kind of private visual channel.
This has obvious evolutionary benefits. Signals used in mating or territorial displays can remain conspicuous to other mantis shrimp while staying relatively cryptic to predators. In this sense, the mantis shrimp’s eye is best understood not as a more powerful version of our own, but as a different solution to problems dependent on their very unique context.
Our enduring fascination with mantis shrimp vision stems from our human desire to imagine (or at least try to imagine) experiences that are beyond our own perception. From this perspective, the idea of there being another creature that might see colors we can’t even conceive of is undeniably compelling.
Yes, mantis shrimp can indeed detect parts of the light spectrum that are invisible to us. Yes, their eyes contain an extraordinary diversity of photoreceptors. However, their visual system still doesn’t seem to prioritize the kind of rich, comparative color processing that our vision does.
Instead, mantis shrimp made a different set of evolutionary trade-offs: they came to favor speed, efficiency and ecological relevance over perceptual depth. This forces us to rethink the assumptions we maintain regarding the criteria for “good” perception. Because often, evolution isn’t about seeing more. It’s about seeing what matters, faster.
From the mantis shrimp to the ecosystems it inhabits, nature is full of hidden perspectives. Measure your connection to it with this science-backed test: Connectedness to Nature Scale
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