Editing Color vision (section)

== Color vision in nonhumans ==
Many species can see light with frequencies outside the human "[[visible spectrum]]". [[Bee]]s and many other insects can detect ultraviolet light,<ref>{{Cite book |title=World Book |date=2022 |publisher=World Book, Inc. |isbn=9780716601227 |edition=72nd |location=Chicago, IL |publication-date=2022 |pages=819}}</ref> which helps them to find [[nectar]] in flowers. Plant species that depend on insect pollination may owe reproductive success to ultraviolet "colors" and patterns rather than how colorful they appear to humans. Birds, too, can see into the ultraviolet (300–400&nbsp;nm), and some have sex-dependent markings on their plumage that are visible only in the ultraviolet range.<ref>{{cite book| vauthors = Cuthill IC |author-link=Innes Cuthill | veditors = Slater PJ |title=Advances in the Study of Behavior|publisher=Academic Press|location=Oxford, England|year=1997|volume=29|chapter=Ultraviolet vision in birds|page=161|isbn=978-0-12-004529-7}}</ref><ref>{{cite book| vauthors = Jamieson BG |title=Reproductive Biology and Phylogeny of Birds|publisher=University of Virginia|location=Charlottesville VA|year=2007|page=128|isbn=978-1-57808-386-2}}</ref> Many animals that can see into the ultraviolet range, however, cannot see red light or any other reddish wavelengths.  For example, bees' visible spectrum ends at about 590&nbsp;nm, just before the orange wavelengths start. Birds, however, can see some red wavelengths, although not as far into the light spectrum as humans.<ref name = "Varela_1993">{{cite book | vauthors = Varela FJ, Palacios AG, Goldsmith TH | chapter = Color vision of birds | pages = 77–94 | chapter-url = https://books.google.com/books?id=p1SUzc5GUVcC | veditors = Zeigler HP, Bischof HJ | publisher = MIT Press | date = 1993 | title = Vision, Brain, and Behavior in Birds |isbn=978-0-262-24036-9}}</ref> It is a myth that the common goldfish is the only animal that can see both infrared and ultraviolet light;<ref>{{cite web |url= http://www.skeptive.com/disputes/4484 |title=True or False? The common goldfish is the only animal that can see both infrared and ultra-violet light. | work = Skeptive |access-date=September 28, 2013 |url-status=usurped |archive-url=https://web.archive.org/web/20131224110616/http://www.skeptive.com/disputes/4484 |archive-date=December 24, 2013 }}</ref> their color vision extends into the ultraviolet but not the infrared.<ref>{{cite book | vauthors = Neumeyer C | veditors = Lazareva O, Shimizu T, Wasserman E |title= How Animals See the World: Comparative Behavior, Biology, and Evolution of Vision |publisher=Oxford Scholarship Online |year=2012 |chapter=Chapter 2: Color Vision in Goldfish and Other Vertebrates |isbn= 978-0-195-33465-4}}</ref>

The basis for this variation is the number of cone types that differ between species. Mammals, in general, have a color vision of a limited type, and usually have [[red–green color blindness]], with only two types of cones. Humans, some primates, and some marsupials see an extended range of colors, but only by comparison with other mammals. Most non-mammalian vertebrate species distinguish different colors at least as well as humans, and many species of birds, fish, reptiles, and amphibians, and some invertebrates, have more than three cone types and probably superior color vision to humans.

In most [[Catarrhini]] (Old World monkeys and apes—primates closely related to humans), there are three types of [[color receptors]] (known as [[cone cell]]s), resulting in [[trichromatic color vision]]. These primates, like humans, are known as [[Trichromacy|trichromats]]. Many other primates (including New World monkeys) and other mammals are [[dichromat]]s, which is the general color vision state for mammals that are active during the day (i.e., felines, canines, ungulates). Nocturnal mammals may have little or no color vision. Trichromat non-primate mammals are rare.<ref name="Ali_1985">{{cite book| vauthors = Ali MA, Klyne MA |title=Vision in Vertebrates|place=New York|publisher=Plenum Press|year=1985 |isbn=978-0-306-42065-8}}</ref>{{rp|174–175}}<ref>{{cite journal | vauthors = Jacobs GH | title = The distribution and nature of colour vision among the mammals | journal = Biological Reviews of the Cambridge Philosophical Society | volume = 68 | issue = 3 | pages = 413–71 | date = August 1993 | pmid = 8347768 | doi = 10.1111/j.1469-185X.1993.tb00738.x | s2cid = 24172719 }}</ref>

Many [[invertebrate]]s have color vision. [[Honeybee]]s and [[bumblebee]]s have trichromatic color vision which is insensitive to red but sensitive to ultraviolet. ''[[Osmia rufa]]'', for example, possess a trichromatic color system, which they use in foraging for pollen from flowers.<ref>{{cite journal|title = Spectral Sensitivity of Photoreceptors and Colour Vision in the Solitary Bee, Osmia Rufa|url = http://jeb.biologists.org/content/136/1/35|journal = Journal of Experimental Biology|date = 1988-05-01|issn = 0022-0949|pages = 35–52|volume = 136|issue = 1| vauthors = Menzel R, Steinmann E, De Souza J, Backhaus W |doi = 10.1242/jeb.136.1.35|url-status = live|archive-url = https://web.archive.org/web/20160304133039/http://jeb.biologists.org/content/136/1/35|archive-date = 2016-03-04}}</ref> In view of the importance of color vision to bees one might expect these receptor sensitivities to reflect their specific visual ecology; for example the types of flowers that they visit. However, the main groups of [[hymenoptera]]n insects excluding ants (i.e., bees, wasps and [[sawfly|sawflies]]) mostly have three types of photoreceptor, with spectral sensitivities similar to the honeybee's.<ref name="Osorio_2008">{{cite journal | vauthors = Osorio D, Vorobyev M | title = A review of the evolution of animal colour vision and visual communication signals | journal = Vision Research | volume = 48 | issue = 20 | pages = 2042–51 | date = September 2008 | pmid = 18627773 | doi = 10.1016/j.visres.2008.06.018 | s2cid = 12025276 | doi-access = free }}</ref>'' [[Papilio]]'' butterflies possess six types of photoreceptors and may have pentachromatic vision.<ref>{{cite journal | vauthors = Arikawa K | title = Spectral organization of the eye of a butterfly, Papilio | journal = Journal of Comparative Physiology A: Neuroethology, Sensory, Neural & Behavioral Physiology | volume = 189 | issue = 11 | pages = 791–800 | date = November 2003 | pmid = 14520495 | doi = 10.1007/s00359-003-0454-7 | s2cid = 25685593 }}</ref> The most complex color vision system in the animal kingdom has been found in [[stomatopod]]s (such as the [[mantis shrimp]]) having between 12 and 16 spectral receptor types thought to work as multiple dichromatic units.<ref>{{cite journal |vauthors=Cronin TW, Marshall NJ |title=A retina with at least ten spectral types of photoreceptors in a mantis shrimp |journal=Nature |volume=339 |pages=137–40 |year=1989 |doi=10.1038/339137a0 |issue=6220 |bibcode=1989Natur.339..137C |s2cid=4367079 }}</ref>

Vertebrate animals such as [[tropical fish]] and birds sometimes have more complex color vision systems than humans; thus the many subtle colors they exhibit generally serve as direct signals for other fish or birds, and not to signal mammals.<ref>{{cite journal | vauthors = Kelber A, Vorobyev M, Osorio D | title = Animal colour vision--behavioural tests and physiological concepts | journal = Biological Reviews of the Cambridge Philosophical Society | volume = 78 | issue = 1 | pages = 81–118 | date = February 2003 | pmid = 12620062 | doi = 10.1017/S1464793102005985 | s2cid = 7610125 | url = https://lup.lub.lu.se/record/131377 }}</ref> In [[bird vision]], [[tetrachromacy]] is achieved through up to four [[Cone cell|cone]] types, depending on species. Each single cone contains one of the four main types of vertebrate cone [[photopigment]] (LWS/ MWS, RH2, SWS2 and SWS1) and has a colored [[oil droplet]] in its inner segment.<ref name="Osorio_2008"/> Brightly colored oil droplets inside the cones shift or narrow the spectral sensitivity of the cell. [[Pigeon]]s may be [[pentachromat]]s.<ref>{{cite book | vauthors = Thompson E | chapter = Introducing Comparative Colour Vision |title=Colour vision : a study in cognitive science and the philosophy of perception |date=1995 |publisher=Routledge |location=London |isbn=978-0-203-41767-6 | page = 149 | chapter-url = https://books.google.com/books?id=fB0madWbjBIC&pg=PA149 }}</ref>

Reptiles and amphibians also have four cone types (occasionally five), and probably see at least the same number of colors that humans do, or perhaps more. In addition, some nocturnal [[gecko]]s and [[frog]]s have the capability of seeing color in dim light.<ref name="GeckoNocturnalVision">{{cite journal | vauthors = Roth LS, Lundström L, Kelber A, Kröger RH, Unsbo P | title = The pupils and optical systems of gecko eyes | journal = Journal of Vision | volume = 9 | issue = 3 | pages = 27.1–11 | date = March 2009 | pmid = 19757966 | doi = 10.1167/9.3.27 | doi-access = free }}</ref><ref name="AmphibianNocturnalVision">{{cite journal | vauthors = Yovanovich CA, Koskela SM, Nevala N, Kondrashev SL, Kelber A, Donner K | title = The dual rod system of amphibians supports colour discrimination at the absolute visual threshold | journal = Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences | volume = 372 | issue = 1717 | date = April 2017 | pmid = 28193811 | pmc = 5312016 | doi = 10.1098/rstb.2016.0066 | doi-access = free }}</ref> At least some color-guided behaviors in amphibians have also been shown to be wholly innate, developing even in visually deprived animals.<ref name="InnateColorBehaviors">{{cite journal | vauthors = Hunt JE, Bruno JR, Pratt KG | title = An Innate Color Preference Displayed by ''Xenopus'' Tadpoles Is Persistent and Requires the Tegmentum | journal = Frontiers in Behavioral Neuroscience | volume = 14 | issue = 71 | pages = 71 | date = May 12, 2020 | pmid = 32477078 | pmc = 7235192 | doi = 10.3389/fnbeh.2020.00071 | doi-access = free }}</ref>

In the [[evolution of mammals]], segments of color vision were lost, then for a few species of primates, regained by [[gene duplication]]. [[Eutherian]] mammals other than primates (for example, dogs, mammalian farm animals) generally have less-effective two-receptor ([[dichromat]]ic) color perception systems, which distinguish blue, green, and yellow—but cannot distinguish oranges and reds. There is some evidence that a few mammals, such as cats, have redeveloped the ability to distinguish longer wavelength colors, in at least a limited way, via one-amino-acid mutations in opsin genes.<ref>Shozo Yokoyama and F. Bernhard Radlwimmera, "The Molecular Genetics of Red and Green Color Vision in Mammals", Genetics, Vol. 153, 919–932, October 1999.</ref>  The adaptation to see reds is particularly important for primate mammals, since it leads to the identification of fruits, and also newly sprouting reddish leaves, which are particularly nutritious.

However, even among primates, full color vision differs between New World and Old World monkeys. Old World primates, including monkeys and all apes, have vision similar to humans. [[New World monkeys]] may or may not have color sensitivity at this level: in most species, males are dichromats, and about 60% of females are trichromats, but the [[owl monkey]]s are cone [[monochromacy|monochromats]], and both sexes of [[howler monkey]]s are trichromats.<ref>{{cite journal | vauthors = Jacobs GH, Deegan JF | title = Photopigments and colour vision in New World monkeys from the family Atelidae | journal = Proceedings. Biological Sciences | volume = 268 | issue = 1468 | pages = 695–702 | date = April 2001 | pmid = 11321057 | pmc = 1088658 | doi = 10.1098/rspb.2000.1421 }}</ref><ref>{{cite journal | vauthors = Jacobs GH, Deegan JF, Neitz J, Crognale MA, Neitz M | title = Photopigments and color vision in the nocturnal monkey, Aotus | journal = Vision Research | volume = 33 | issue = 13 | pages = 1773–83 | date = September 1993 | pmid = 8266633 | doi = 10.1016/0042-6989(93)90168-V | s2cid = 3745725 | citeseerx = 10.1.1.568.1560 }}</ref><ref>{{cite journal | vauthors = Mollon JD, Bowmaker JK, Jacobs GH | title = Variations of colour vision in a New World primate can be explained by polymorphism of retinal photopigments | journal = Proceedings of the Royal Society of London. Series B, Biological Sciences | volume = 222 | issue = 1228 | pages = 373–99 | date = September 1984 | pmid = 6149558 | doi = 10.1098/rspb.1984.0071 | s2cid = 24416536 | bibcode = 1984RSPSB.222..373M }}</ref><ref>{{cite book | vauthors = Sternberg RJ | date = 2006 | title = Cognitive Psychology | edition = 4th | publisher = Thomson Wadsworth }}</ref> Visual sensitivity differences between males and females in a single species is due to the gene for yellow-green sensitive [[opsin]] protein (which confers ability to differentiate red from green) residing on the X sex chromosome.

Several [[marsupial]]s, such as the [[fat-tailed dunnart]] (''Sminthopsis crassicaudata''), have trichromatic color vision.<ref>{{cite journal | vauthors = Arrese CA, Beazley LD, Neumeyer C | title = Behavioural evidence for marsupial trichromacy | journal = Current Biology | volume = 16 | issue = 6 | pages = R193-4 | date = March 2006 | pmid = 16546067 | doi = 10.1016/j.cub.2006.02.036 | doi-access = free | bibcode = 2006CBio...16.R193A }}</ref>

[[Marine mammal]]s, adapted for low-light vision, have only a single cone type and are thus [[monochromat]]s.{{Citation needed|date=September 2010}}