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Bottlenose dolphin vision: the science and the numbers

Tursiops truncatus · order Cetacea · Mammals: all the numbers

Dolphins have one cone type, so no colour vision in daylight.[1] Their sharpest vision resolves 3.4 cycles per degree, against 63.75 for people in this dataset.[6][7]

See it on your photoBack to How do dolphins see?
  • 1colour receptor classMeasured
  • 3.4cycles per degree (sharpness)Measured*

The bottlenose dolphin (Tursiops truncatus) is a mammal in the order Cetacea. Its eyes belong to the vision type Marine mammal cone monochromat: a single cone type, so no hue at all, in a rod-dominated eye. Measured in this species: colour, sharpness, foveas and night vision. Measured core: measured values on at least 3 of the 6 dials.

This is a simulation built from published eye measurements, not what the animal experiences.

Method: How we know what animals see (the See Like Animals vision engine) · Sources · Last updated . Every value below carries its evidence level and sources; nothing is typed by hand.

What dolphins see: colour receptors

Bottlenose dolphin colour receptor peaks, 300 to 700 nmBottlenose dolphin: 1 receptor peak at 524 nm; you: 3 at 421.5, 532, 558.4 nm. ultraviolet300400500600700
Bottlenose dolphin: 524 nmPeople: 421.5, 532, 558.4 nmWavelength in nanometres

What stands out

  • It has one receptor class for colour, so it sees brightness but no hue.
  • Its sharpest vision resolves 3.4 cycles per degree: the finest stripe pattern it can tell apart from grey.
  • Activity pattern: cathemeral.

The six dials

Evidence levels: how the tiers work. "Measured" means a value measured in this species; "Estimated" values come from a close relative or an eye-size formula. The last column gives the values for people from the same catalogue.

Vision values for the bottlenose dolphin (Tursiops truncatus), catalogue-v1
DialValueEvidenceSourcesPeople
ColourColour receptors
1 receptor class: 524 nm (MWS (green))
measured in this species
Measured[1]Colour receptors: 3 receptor classes: 421.5 nm (VS/SWS (violet)), 532 nm (MWS (green)), 558.4 nm (LWS (long)) Measured (not re-verified)[2][3][4][5]
SharpnessAcuity
3.4 cycles per degree
median of 2 behavioural rows (method priority rule); acuity_cpd: in-air rows (aquatic animal: in-water rows used) set aside (labelled alternative: 2.05)
Measured (not re-verified)[6][7]Acuity: 63.75 cycles per degree Measured[7][8]
Field of viewBinocular overlap
75°
median of 41 relatives in class Mammalia: Octodon degus, Octodon lunatus, Equus caballus, Ovis aries, Bos taurus, Capra hircus
Group default[9][10][11][12]Binocular overlap: 122.5° Measured[9][10]
Total field of view: 200° Measured (not re-verified)[13]
Blind area behind the head: 160° Derived[13]
Eye placement: frontal Derived[9][10]
Eye placement
frontal		Group default[9][10][11][12]
Sharp zones (foveas)Number of foveas
0
fovea_present / area_centralis_type (retinal topography; count 1 = fovea present, 0 = none)
Measured[14]Number of foveas: 1 Measured[14]
Fovea type: fovea Measured[14]
Fovea type
area centralis, horizontal streak		Measured[14]
Night visionActivity pattern
cathemeral
tie ['cathemeral', 'diurnal'] broken by species-level studies (round-3 tie-break rule 2) (of 5 rows): aquatic; arrhythmic/cathemeral; diurnal; mesopic
Measured (not re-verified)[15][16][17][18][19]Activity pattern: diurnal Measured (not re-verified)[15][16][17][2][20][21][18][19]
Pupil shape: vertical Group default[22][23]
Reflective layer (tapetum): no Measured[24]
Rods vs cones: cone-dominated Derived[15][16][17][2][20][21][18][19]
Pupil shape
vertical		Group default[22][23]
Reflective layer (tapetum)
yes		Measured (not re-verified)[25]
Rods vs cones
mixed
nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated
Derived[15][16][17][18][19]
Motion (flicker fusion)Flicker fusion frequency
60 Hz
median of 21 relatives in class Mammalia: Rattus norvegicus, Cavia porcellus, Mus musculus, Felis catus, Macaca mulatta, Macaca nemestrina
Group default[26][27][28][29]Flicker fusion frequency: 60 Hz Measured[27][28]

All mammals side by side: Mammals: every measurement. Method: how we know what animals see.

Sources

  1. Frazer et al. 2024
  2. Longcore 2023
  3. Kirwan
  4. Müller et al. 2009
  5. Thermal Activation and Photoactivation of Visual… 2004
  6. Caves et al. 2024
  7. Kirk et al. 2004
  8. Veilleux et al. 2014
  9. Heesy 2004
  10. Heffner et al. 1992
  11. Vega-Zuniga et al. 2013
  12. Vega-Zuniga et al. 2017
  13. Campbell & Green 1965
  14. Kopania et al. 2025
  15. Anderson et al. 2017
  16. Borges et al. 2018
  17. Wilman et al. 2014
  18. Schmitz et al. 2011
  19. Moura et al. 2024
  20. Maor et al. 2017
  21. Jones et al. 2009
  22. Banks et al. 2015
  23. Cervino et al. 2021
  24. Guareschi et al. 2025
  25. Standard textbook knowledge
  26. Haarlem et al. 2026
  27. Healy et al. 2013
  28. Inger et al. 2014
  29. Lafitte et al. 2022

Every value cites its sources (all sources). Values were extracted from these works and converted (units, medians, derived values); changes are ours, and the listed sources do not endorse this site. Data: catalogue-v1, built 2026-09-29. Accuracy notes: how accurate is this? Method: how we know.