WHICH ANIMALS HAVE THE BEST EYESIGHT?
Picture yourself as a red-tailed hawk gliding effortlessly in the sky. You examine the terrain, searching for your next meal. You see a squirrel several hundred feet beneath you. Its coat helps it blend into the ground, but its camouflage is no match for your sharp eyesight.
Raptors — including hawks, eagles, and falcons- are known for their hyper-focused vision. But you might wonder if these birds really come out on top, or if other animals have even more impressive eyesight.
So, what animal has the best vision? In reality, there's no easy answer, but there are certainly some standouts.
"There is no perfect visual system," Esteban Fernandez-Juricic, a professor of biological sciences at Purdue University. He clarified that, when viewed through an evolutionary Perspective, the development of sophisticated visual systems is incredibly expensive. This is because the eyes are a significant part of the nervous system, which requires considerable energy. To maintain efficiency, evolution compels animals to create only the visual systems necessary for their surroundings and behaviour.
Most colorful vision: mantis shrimp
In the realm of animal color vision, the mantis shrimp stands out as the undisputed champion. These strange invertebrates inhabit shallow ocean waters, and they might perceive colors beyond our understanding.
To comprehend how mantis shrimp perceive their surroundings, it's essential to grasp the mechanics of color vision. Humans possess three varieties of photoreceptor cells that respond to various light wavelengths, approximately aligning with red, blue, and green. Numerous vertebrates possess four varieties of photoreceptors, indicating that our color vision is inferior to that of several other species.
"Most other animals have better color vision than we do," said Justin Marshall, a professor emeritus at the University of Queensland in Australia with a specialty in marine animal eye and brain structure and function. "We're comparatively colorblind monkeys."
Mantis shrimp possess an astonishingly greater quantity of photoreceptors, however. Marshall states that these crustaceans possess 12 varieties of color photoreceptors. Certain receptors are specifically adapted to sense light in the ultraviolet spectrum, probably causing the mantis shrimp's perception of the world to differ significantly from ours. Mantis shrimp also have special photoreceptors that can detect the polarization of light, a feature of light waves that derives from how sunlight scatters through Earth's atmosphere.
However, the specifics of how the mantis shrimp brain manages all this information remain uncertain. Their brains might be recognizing patterns in color combinations instead of identifying distinct inputs from photoreceptors. "They're probably not trying to see four times as much color as us, they're just decoding the information in a different way," Marshall explained.
Fastest vision: insects
Our perception might seem like an ongoing flow, yet there is a restriction on the speed at which our eyes and minds can interpret information. According to Cronin, humans perceive visual information at approximately 60 frames every second. Conversely, our creepy-crawly companions can process significantly more visual details in the same timeframe.
Most insects' visual systems can take in hundreds of images every second. That's so quick that fluorescent lights, which flicker at or below the visible rate for human eyesight, would appear as strobe lights to them.
"If a fly were to fly into a movie theater, it would just think it's watching a really fast slideshow," Cronin explained.
This incredibly fast vision is why it's so difficult to swat a fly; they can actually see us approaching before we realize it. Flies achieve this due to their minuscule bodies, which allow electrical signals between their eyes and brain to cover a shorter distance, resulting in quicker processing of visual information.
The trade-offs
Each of these unique visual systems is remarkable in distinct ways, yet they also entail sacrifices. For instance, both insects and mantis shrimp possess compound eyes composed of individual subunits. Only a limited number of subunits can be accommodated, resulting in these animals having vision that is significantly lower in resolution than ours, resembling a pixelated image.
Considering these trade-offs, Cronin believes human eyes are sufficient. "People are a pretty good compromise," he said. "I wouldn't want to be a mantis shrimp, because my brain would be the size of a small pea. So I'm happy with what I have, to be honest."
