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Snowy owl vision: the science and the numbers

Bubo scandiacus · order Strigiformes · Birds: all the numbers

Its sharpest vision resolves 38.3 cycles per degree, against 63.75 for people in this dataset.[6] Both eyes see the same 34° in front of it.[9]

See it on your photoBack to How does the snowy owl see?
  • 38.3cycles per degree (sharpness)Measured
  • 34°seen by both eyesMeasured

The snowy owl (Bubo scandiacus) is a bird in the order Strigiformes. Its eyes belong to the vision type Owl and night bird: rod-dominated eyes built for dim light, with low sharpness. Measured in this species: sharpness, field of view 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 the snowy owl sees: colour receptors

Snowy owl colour receptor peaks, 300 to 700 nmSnowy owl: 1 receptor peak at 555 nm; you: 3 at 421.5, 532, 558.4 nm. ultraviolet300400500600700
Snowy owl: 555 nmPeople: 421.5, 532, 558.4 nmWavelength in nanometres

What stands out

  • Its sharpest vision resolves 38.3 cycles per degree: the finest stripe pattern it can tell apart from grey.
  • Both eyes see the same 34° in front of it (binocular overlap), where depth is judged best.
  • 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 snowy owl (Bubo scandiacus), catalogue-v1
DialValueEvidenceSourcesPeople
ColourColour receptors
1 receptor class: 555 nm (LWS (long))
receptor set of nearest measured relative Bubo virginianus (same genus Bubo)
Estimated[1][2]Colour receptors: 3 receptor classes: 421.5 nm (VS/SWS (violet)), 532 nm (MWS (green)), 558.4 nm (LWS (long)) Measured (not re-verified)[1][3][4][5]
SharpnessAcuity
38.3 cycles per degree
median of 1 anatomical-ganglion rows (method priority rule)
Measured[6]Acuity: 63.75 cycles per degree Measured[7][8]
Field of viewBinocular overlap
34°
median of 1 rows (eyes-at-rest rows preferred)
Measured[9]Binocular overlap: 122.5° Measured[10][11]
Total field of view: 200° Measured (not re-verified)[12]
Blind area behind the head: 160° Derived[12]
Eye placement: frontal Derived[10][11]
Total field of view
201°
median species-v1 total field of family Strigidae: Strix aluco
Estimated[13]
Blind area behind the head
159°		Estimated[13]
Eye placement
lateral
frontal if binocular overlap >= 60 deg, else lateral
Derived[9]
Sharp zones (foveas)Number of foveas
1
median of 48 relatives in class Aves: Branta canadensis, Cardinalis cardinalis, Passerina cyanea, Zenaida macroura, Cyanocitta cristata, Junco hyemalis
Group default[14][15][16]Number of foveas: 1 Measured[17]
Fovea type: fovea Measured[17]
Fovea type
single central fovea (displaced dorso-temporally from retinal centre)		Group default[14][15][16]
Night visionActivity pattern
cathemeral
tie ['cathemeral', 'nocturnal'] broken by species-level studies (round-3 tie-break rule 2) (of 5 rows): cathemeral; nocturnal; photopic
Measured (not re-verified)[18][19][20][21][22]Activity pattern: diurnal Measured (not re-verified)[23][24][25][1][26][27][21][22]
Pupil shape: vertical Group default[28][29]
Reflective layer (tapetum): no Measured[30]
Rods vs cones: cone-dominated Derived[23][24][25][1][26][27][21][22]
Reflective layer (tapetum)
no		Estimated[31]
Rods vs cones
mixed
nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated
Derived[18][19][20][21][22]
Motion (flicker fusion)Flicker fusion frequency
40 Hz
median of 1 relatives in genus Bubo: Bubo virginianus
Estimated[32]Flicker fusion frequency: 60 Hz Measured[33][34]

All birds side by side: Birds: every measurement. Method: how we know what animals see.

Sources

  1. Longcore 2023
  2. VPOD in-vivo (MSP / single-cell) lambda… 2025
  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. Potier et al. 2023
  10. Heesy 2004
  11. Heffner et al. 1992
  12. Campbell & Green 1965
  13. Martin 1984
  14. Moore et al. 2017
  15. Potier et al. 2017
  16. Rodrigues et al. 2026
  17. Kopania et al. 2025
  18. Light conditions and the evolution of…
  19. Choiniere et al. 2021
  20. Wilman et al. 2014
  21. Schmitz et al. 2011
  22. Moura et al. 2024
  23. Anderson et al. 2017
  24. Borges et al. 2018
  25. Wilman et al. 2014
  26. Maor et al. 2017
  27. Jones et al. 2009
  28. Banks et al. 2015
  29. Cervino et al. 2021
  30. Guareschi et al. 2025
  31. Healy et al. 2013
  32. Lafitte et al. 2022
  33. Healy et al. 2013
  34. Inger et al. 2014

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.