This question is worded kind of weirdly, but I was wondering why humans are able to see so many colors. I didn’t want to just ask “why/how can humans see so many colors?” because I didn’t want to get the generic answer of how the eye works. Snakes can see infrared light to detect body heat of prey, insects and spiders see ultraviolet light (for locating and pollinating plants I believe), but humans? Why are we able to see all visible light (aka the rainbow) when other animals have limited color vision for one survival reason or another?
In: Biology
Fruit changes colour when it ripens if you can see colours you can tell which fruit is ripe, in addition most camouflage evolved to be used against creatures which can’t see some colours.
I mean it kind of becomes a philosophical question because if we met some aliens who could only see like, the red to yellow part of the spectrum, they wouldn’t say, “we see only red and yellow, but humans see more colors”, they would say that they see a range of visible colors (possibly with many more names to distinguish the different shades,) and humans, surprisingly, can see “ultra-yellow” in addition to the “whole” visible spectrum. Because what we call the visible spectrum is called that because that’s the range that we can see, and we give the colors we can distinguish names within that spectrum. But if it were different, we would still think of it the same way, and still have a bunch of names for the colors we could distinguish
To put it another way: it isn’t really the case that we evolved to see a variety of colors, and other animals didn’t. Because those colors, conceptually and linguistically, were invented *after* evolution gave us the ability to distinguish different parts of the electromagnetic spectrum
We’re omnivores. We have to be able to tell ripe berries from unripe ones and identify prey animals in their natural habitat. Plus we’re also a prey animal to other predators, so we have to be able to see them as well. Few animals are as flexible.
Wide range? Humans see a pretty restricted 400-700 nm wavelength, and our eyes are most sensitive to green – probably because there’s a lot of green around in the form of plants.
Meanwhile lions can see into the infrared spectrum, giving them natural night vision for hunting. And birds can see into the ultraviolet spectrum.
Many animals are incapable of seeing the difference in color between orange and green. This is why many jungle predators can be predominately orange despite needing to blend in with leaves.
That’s not the only reason, but it is handy that homo sapiens is among the few animals that can see a hidden tiger.
Sometimes.
Another reason so many mammals don’t have good color vision is that at a point in mammal evolution, most mammals were nocturnal to avoid the reptile apex predators. Those mammals lost color vision because it’s not needed at night. When the big reptiles went extinct, mammals could come out during the day again, and they slowly regained some color vision. But scent remains the strongest sense for most mammals, a sense that’s important for a nocturnal animal.
Most *mammals* can only see limited colors.
Birds have excellent color vision, and their dinosaur ancestors probably did for a hundred million years, too.
Mammals spent the first 50 million years of our history as small, nocturnal, burrowing critters while dinosaurs occupied all the dominant daytime niches. Along with fur, some fundamental mammal adaptations resulted in much better sense of hearing and smell than dinos/birds/reptiles, and much better low-light vision than daytime color vision.
Those adaptations are still with us. Most mammal species are nocturnal or active at dawn/dusk, and almost all rely on sound & smell more than vision. Primates are a real outlier, and there’s multiple theories for why we got such good color vision (sharp vision, too). Finding fruit? Grabbing the right branch? My personal favorite theory is that our monkey ancestors needed good sharp vision to detect snakes that hunted them. Primates on Madagascar and S America don’t have natural snake predators and don’t have highly developed daytime vision.
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