General Question

Mr_M's avatar

Besides man, what other animals need light to see?

Asked by Mr_M (7591points) August 10th, 2008

I believe most animals can see in the dark and very few need light?

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13 Answers

lefteh's avatar

Every animal needs light to see. The difference is how much light is needed. The difference here lies in the possession of a tapetum lucidum, which is a tissue layer in the eye that sort of enhances the light available. It is true, however, that a large amount of animals possess the tapetum lucidum, and so the humans are in a minority with our pitiable low-light vision.

Mr_M's avatar

So what other animals have pitiable low light vision?

XCNuse's avatar

all the animals you don’t see at night :D

..what.. it’s a semi true statement lol

lefteh's avatar

@Mr_M: I’m not sure. Perhaps one of Fluther’s many animal experts will jump in.

nikipedia's avatar

@lefteh: Also, it depends on what kind of light. Lots of animals (including many kinds of vertebrates) can make use of the UV part of the spectrum.

lefteh's avatar

@niki: Great point. I didn’t even think about that.

syz's avatar

All animals use light to see. Some are more efficient at it than others.

A few animals have unique methods of perceiving the world around them (sonar for bats and dophins, for example, and ampullae of Lorenzini of sharks that pick up electrical impulses, temperature receptors in some insects) but they do not “see” with them.

As a rough way of estimating low light vision, most species who see well in low light have proportionally large eyes (http://en.wikipedia.org/wiki/Slow_loris).

wabarr's avatar

There is an anatomical trade-off between the visual ability to resolve fine detail in high light conditions (visual acuity) and the ability to detect shapes and motions in low light conditions (visual sensitivity). In other words, if you are really good at one, you must be really bad at the other. Humans have really good visual acuity, and thus have reduced sensitivity. However, it is not just humans. All haplorhines, the group of primates including tarsiers, monkeys, and apes (including humans), posses very high acuity compared to most mammals. Diurnal birds of prey like eagles also have ridiculously high acuity.

Mr_M's avatar

So let me move this discussion in a different direction. I feel, since man is one of few species on earth that need lights, wouldn’t one expect it to be RARE that an extraterrestrial species would need lights, such that a UFO with lights would make no sense? Why would an extraterrestrial species, THAT DOESN’T WANT TO BE DETECTED, put lights on the craft? I think as soon as someone reports they saw a UFO with lights at night, then it can’t be a UFO?

lefteh's avatar

@Mr_M: I thought that we established that all animals need light to see.

Mr_M's avatar

This time I’m talking [electric, artificial] “lights”. I guess another way of saying it is “If (ex.) animals could build a spaceship, odds are they wouldn’t include lighting since most species [except man] don’t need artificial lighting, so is it safe to say the odds are that alien spacecraft would not, logically, have lighting? From this, then, can’t we conclude that if a “UFO” has lights on it, it probably is NOT an extraterrestrial UFO?

lefteh's avatar

No…
Did you read wabarr’s post about acuity? If you’re piloting an aircraft, you’re probably going to need to have high visual acuity. With high visual acuity generally comes the need for a well-lit environment.

Mr_M's avatar

Good point.

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