How they see
How does a dolphin see the world?
A monochrome ocean, guided by sonar
A dolphin's eyes work in two worlds, staying sharp both under water and up in the air, though they paint that world without colour. Missing the blue cone, a dolphin sees only in shades of brightness, tuned to the blue-green of the sea. Much of its 'seeing', in truth, is done with sound, its echolocation sketching a picture that vision alone could never provide.
See through their eyes
Human ≈ 60 cpd (20/10)
How sharp is a dolphin's vision?
Its eyes resolve about 2.5 cycles per degree (20/240), while a human reaches around 60 cpd (20/10). Its field of view spans about 300°.
How does a dolphin see a human?
Its eyes resolve about 2.5 cycles per degree against your 60, so a face has to be roughly 24 times closer for it to pick out the detail you do. Your outline and your movement read clearly; your expression does not.
Colour comparison
How each colour shifts when seen through this animal's eyes, using the same colour model as the app. Tones a screen can't emit (such as ultraviolet) are shown as an approximation.
What colours can a dolphin see?
Essentially colour-blind; sees the underwater world in shades of brightness, tuned to blue-green water.
Photoreceptors
Cone monochromat (blue cone absent) + rods
Cone peak sensitivities
- Single L cone524 nm
How does a dolphin see in the dark?
Rod-rich retina and tapetum for deep, dim water.
How does a dolphin's vision compare to a human's?
What a dolphin can do that you cannot is focus equally well in water and air; dip below the surface and your own vision blurs. In plain detail it sees around 20/240 to your 20/20, and no colour to your millions.
What is special about a dolphin's vision?
- Amphibious focus (sharp in water and air)
- Echolocation is the primary distance sense
- Double retinal areas of high acuity
What the research shows
Evidence for a dolphin's colour blindness comes from its visual pigments rather than from behaviour. Fasick & Robinson (1998) characterised the spectral tuning of the dolphin rod pigment, near 488 nm, and of its single cone pigment, near 524 nm, both shifted towards blue compared with land mammals. Peichl, Behrmann & Kröger (2001) placed this in a wider pattern: whales and seals have lost the short-wavelength cone, leaving one cone class and therefore nothing to compare hues against.
Acuity has been measured in two independent ways that land close together. Herman, Peacock, Yunker & Madsen (1975) tested dolphins behaviourally with gratings and found a resolution of about 12.6 minutes of arc, roughly 2.4 cpd, similar in air and in water, which they attributed to the double-slit pupil that forms in bright light. Mass & Supin (1995) worked from retinal ganglion-cell density and estimated about 9 minutes of arc in water and 12 in air, roughly 3.3 and 2.5 cpd. The page uses 2.5 cpd, shown as 20/240. Flicker fusion is poorly quantified, so no value is given. Echolocation supplies much of a dolphin's sense of distance and shape, and a single blue-green greyscale frame can show the loss of colour but not the acoustic picture that fills in what vision leaves out.
Guides: Are animals colour blind? · Which animal has the best eyesight? · All guides
Scientific sources
- Fasick & Robinson (2000)
- Griebel & Schmid (2002)
- Herman et al. (1975)
- Mass & Supin (1995)
Download Animal Vision
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