Chameleons are amazing lizards that have the ability to change the color and pattern of their skin. This allows them to blend in with their surroundings as camouflage and communicate with other chameleons. But how does changing color affect what chameleons see? Here we’ll explore what colors chameleons can see, how their eyes work, and how their color vision compares to humans.
The chameleon eye
Chameleons have incredibly unique and complex eyes that allow them to see in two directions at once. Their eyes can operate independently, with each eye able to focus separately on different objects. This gives chameleons a full 360 degree arc of vision around their body.
Each chameleon eye has a cone-shaped bulge at the back, made up of layers of specialized cells. This allows the chameleon to see sharp images from a distance. The chameleon’s eyes can rotate and swivel quickly to track passing insects and keep watch for predators.
Color perception
Chameleons have color vision that works differently than human color vision. Humans have three types of color receptors, or cones, that detect red, blue, and green light. The combination of signals from these three cone types allows us to see the full spectrum of colors.
Chameleons, on the other hand, have two cone types – one for blue and one for green. They are missing the third cone for red light. However, chameleons have an additional type of light receptor, called a double cone, which is thought to allow them to see some red colors.
So while chameleons can only perceive colors in the blue-green range, their double cones extend their vision partly into the red range. The combination of these visual receptors lets chameleons see in the ultraviolet spectrum beyond what humans can see.
Camouflage and color change
A chameleon’s ability to change color comes from pigment cells, called chromatophores, in their skin. The upper layers of a chameleon’s skin contain melanophores packed with black and brown pigments, as well as iridophores that reflect blue and white light.
Deeper layers house the yellow and red pigments of the xanthophores and erythrophores. By adjusting the space between the pigment cells, chameleons can shift their skin between different colors.
| Chromatophore | Pigment Color |
|---|---|
| Melanophores | Blacks/browns |
| Iridophores | Blues/whites |
| Xanthophores | Yellows |
| Erythrophores | Reds |
Chameleons change color through combinations of yellow, red, blue, black, and brown. Even though chameleons can’t see the full color spectrum, their color vision is well-tuned to the colors of their environment. This allows them to blend in seamlessly.
Uneven color distribution
When a chameleon changes color, it doesn’t necessarily change its entire body to the same shade. Chameleons can control color change in localized patches across their skin. This allows them to display multiple colors and patterns at once for camouflage.
Some chameleon species, like the panther chameleon, also have uneven color distribution by default. These chameleons have permanent patterns that provide camouflage, with different patch colors pre-set. The chameleon can then fine-tune the pattern colors to match the environment.
Color signals
In addition to camouflage, chameleons use color change to communicate. The coloring pattern displayed by a chameleon conveys different signals:
| Color Pattern | Signal |
|---|---|
| Dark black, brown, green | Anger, aggression |
| Lighter greens, yellows | Fear, submission |
| Brights reds, oranges | Excitement |
| Spotted/striped patterns | Mating interest |
During mating season, male chameleons will show vibrant, striped displays to attract females. Rival males use darker coloring to signal aggression and scare off competition.
Color vision advantages
A chameleon’s unique color vision gives it several key advantages:
– Camouflage – By changing color and pattern, chameleons can perfectly match their surroundings to avoid predators. Their eyes can also independently scan for threats in a wide visual field.
– Signaling – Bright color displays allow chameleons to communicate territory, mating availability, aggression, and other signals visible to members of their own species.
– Hunting – Color vision helps chameleons pinpoint insects and other small prey against foliage across distances. Their quick color change can also lure prey within striking range.
– Temperature regulation – Darker pigment patterns allow chameleons to absorb heat, while lighter colors reflect heat. This helps regulate temperature.
– Species recognition – Different chameleon species have characteristic patterns. Their color vision allows them to distinguish their own species from others.
Differences from human vision
There are some key differences between chameleon vision and human vision:
– **Color range** – Chameleons can only see colors in the blue-green to red range, while humans see the full spectrum.
– **Tetrachromacy** – With four cone types, chameleons have tetrachromatic vision. Humans are trichromats with three cone types.
– **UV vision** – Chameleons can see into the ultraviolet range, unlike humans.
– **Independent eyes** – Chameleons can look in two directions at the same time with each eye working independently.
– **Focus** – The chameleon eye has greater focusing power and visual acuity for spotting small prey items.
– **Motion perception** – Chameleons have specialized motion-detection receptors that are much more sensitive than in humans.
Conclusion
Chameleons have uniquely adapted vision that allows them to see colors, patterns, and movement in ways that differ from human vision. While they can only perceive a limited color spectrum, their eyes are extremely well-tuned to their environment. Chameleons use color change for camouflage and communication that provides remarkable benefits for survival. Their distinctive eyes allow chameleons to thrive in their habitats and spot both prey and predators. So even though they don’t see the same spectrum of colors we do, chameleons have color vision that is ideal for their needs.
