Are animals colour blind? Which ones, and how much
Most mammals are colour blind in the way some people are: they have two types of cone where we have three, so reds and greens merge. A smaller group — sharks, seals, dolphins and a few others — have essentially one, and see in shades of a single colour. In our catalogue, 14 species are two-cone "dichromats" and 6 are one-cone "monochromats". Plenty of others, especially birds, insects and fish, see more colour than we do.
What "colour blind" means for an animal
Colour vision works by comparing how strongly different cone types respond to the same light. People usually have three cone types, peaking in the blue, green and yellow-green. With two, an animal can still separate blues from yellows, but reds, oranges and greens fall along the same axis and become hard or impossible to tell apart — the same pattern as the commonest forms of human colour blindness. With a single cone type there is nothing to compare, and the world is seen in shades of one colour, graded by brightness.
Two colours: the dichromats
Dogs are the best-studied example: their cones peak near 429 and 555 nm, and they cannot tell red from green. The same is true of horses, cattle, pigs, goats and sheep. It also settles a popular myth. Bulls, with cones near 451 and 555 nm, do not see a matador's cape as red: behavioural work (Jacobs et al., 1998) shows cattle separating blue or green from red, but struggling between blue and green, and it is the movement of the cape, not its colour, that provokes the charge.
| Animal | Cone peaks | Receptors |
|---|---|---|
| Dog | 429 nm + 555 nm | Dichromat (2 cone types) + rod-rich retina |
| Cat | 450 nm + 550 nm | Dichromat (2 cone types), heavily rod-dominated |
| Horse | 428 nm + 539 nm | Dichromat (2 cone types) |
| Bull | 451 nm + 555 nm | Dichromat (2 cone types) |
| Rabbit | 425 nm + 520 nm | Dichromat (2 cone types), rod-rich |
| Deer | 455 nm + 537 nm | Dichromat (2 cone types), no UV lens filter |
| Ferret | 430 nm + 558 nm | Dichromat (2 cone types), rod-dominated |
| Elephant | 419 nm + 552 nm | Dichromat (2 cone types), rod-rich |
| Pig | 439 nm + 556 nm | Dichromat (2 cone types) |
| Goat | 451 nm + 553 nm | Dichromat (2 cone types) |
| Sheep | 450 nm + 553 nm | Dichromat (2 cone types) |
| Squirrel | 440 nm + 543 nm | Dichromat (2 cone types), cone-rich (diurnal) |
| Frog | 433 nm + 502 nm | Two rod types (dim-light colour) + cones for day |
| Tiger | 450 nm + 550 nm | Dichromat (2 cone types), rod-rich with tapetum |
One colour: the monochromats
Whales, dolphins and seals have lost the short-wavelength cone that most mammals keep (Peichl, Behrmann & Kröger, 2001), leaving a single cone class, and sharks studied so far also appear to rely on one. In the dim blue light of open water, where few colours reach far anyway, sensitivity matters more than hue. Owls are a special case: they keep some cones, but their retina is so dominated by rods that at night they are effectively monochromats.
| Animal | Cone peak | Receptors |
|---|---|---|
| Shark | 532 nm | Cone monochromat (single cone type) + rods |
| Dolphin | 524 nm | Cone monochromat (blue cone absent) + rods |
| Octopus | 475 nm | Monochromat (single photoreceptor) + polarization sensitivity |
| Seal | 510 nm | Cone monochromat + rod-dominated retina |
| Owl | 503 nm | Rod-dominated, cone-poor (near-monochromat at night) |
| Dragonfish | 530 nm + 705 nm | Rod-dominated, blue-tuned; some species also detect far-red |
And the ones that see more than us
Colour blindness is the rule among mammals, not among animals. Birds, many reptiles and fish have four cone types, and bees and butterflies see into the ultraviolet. See animals that see ultraviolet light for that side of the story, and dog vs cat vision for how two colour-blind species still differ.
Sources
- Banks et al. (2015)
- Byosiere et al. (2018)
- Calderone & Jacobs (2003)
- Carroll, Murphy, Neitz et al. (2001)
- Clark & Clark (2016)
- Donner (2020)
- Douglas et al. (1998)
- Fasick & Robinson (2000)
- Fennell et al. (2019)
- González-Soriano et al. (1997)
- Griebel & Schmid (2002)
- Gruber & Cohen (1985)
- Guenther & Zrenner (1993)
- Hall et al. (2003)
- Hanke et al. (2009)
- Harmening & Wagner (2011)
- Hart, Theiss, Harahush & Collin (2011)
- Herman et al. (1975)
- Jacobs (1993)
- Jacobs et al. (1998)
- Jacobs, Deegan & Neitz (1998)
- Jacobs, Deegan, Neitz, Murphy & Murphy (1994)
- Juliusson et al. (1994)
- Kryger, Amthor & Jacobs (1998)
- Lind et al. (2017)
- Loop, Bruce & Petuchowski (1979)
- Machado, Oliveira & Fernandes (2009)
- Marshall & Messenger (1996)
- Martin (1986)
- Mass & Supin (1995)
- Miller & Murphy (1995)
- Neitz & Jacobs (1989)
- Neitz, Geist & Jacobs (1989)
- Odom, Bromberg & Dawson (1983)
- Partridge & Douglas (1995)
- Peichl, Behrmann & Kröger (2001)
- Phillips & Lomas (2001)
- Pushchin (2019)
- Rehkämper et al. (2000)
- Sikes (1971)
- Stubbs & Stubbs (2016)
- Timney & Keil (1992)
- Van Hooser & Nelson (2006)
- VerCauteren & Pipas (2003)
- Watson et al. (2022)
- Weiffen et al. (2006)
- Yokoyama, Takenaka, Agnew & Shoshani (2005)
- Yovanovich et al. (2017)
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