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King penguin vision: the science and the numbers

Aptenodytes patagonicus · order Sphenisciformes · Birds: all the numbers

Its sharpest vision resolves 20.4 cycles per degree, against 63.75 for people in this dataset.[5] Both eyes see the same 29° in front of it.[8]

See it on your photoBack to How does the king penguin see?
  • 20.4cycles per degree (sharpness)Measured
  • 29°seen by both eyesMeasured

The king penguin (Aptenodytes patagonicus) is a bird in the order Sphenisciformes. Its eyes belong to the vision type Penguin (underwater-tuned bird): cones shifted towards blue, no ultraviolet cone and a flat cornea for focusing under water. Measured in this species: sharpness, field of view and night vision. Measured colour or sharpness: a measured receptor set or acuity in this species; other dials come from relatives or group defaults.

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 king penguin sees: colour receptors

King penguin colour receptor peaks, 300 to 700 nmKing penguin: 3 receptor peaks at 403, 450, 543 nm; you: 3 at 421.5, 532, 558.4 nm. ultraviolet300400500600700
King penguin: 403, 450, 543 nmPeople: 421.5, 532, 558.4 nmWavelength in nanometres

What stands out

  • Its sharpest vision resolves 20.4 cycles per degree: the finest stripe pattern it can tell apart from grey.
  • Both eyes see the same 29° in front of it (binocular overlap), where depth is judged best.
  • Activity pattern: diurnal.

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 king penguin (Aptenodytes patagonicus), catalogue-v1
DialValueEvidenceSourcesPeople
ColourColour receptors
3 receptor classes: 403 nm (VS/SWS (violet)), 450 nm (SWS (blue)), 543 nm (LWS (long))
receptor set of nearest measured relative Spheniscus humboldti (same family Spheniscidae)
Estimated[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)[1][2][3][4]
SharpnessAcuity
20.4 cycles per degree
median of 1 anatomical-ganglion rows (method priority rule)
Measured[5]Acuity: 63.75 cycles per degree Measured[6][7]
Field of viewBinocular overlap
29°
measured in this species (extension 2026-10, fov-verified.csv)
Measured[8]Binocular overlap: 122.5° Measured[9][10]
Total field of view: 200° Measured (not re-verified)[11]
Blind area behind the head: 160° Derived[11]
Eye placement: frontal Derived[9][10]
Total field of view
282°
median species-v1 total field of family Spheniscidae: Spheniscus humboldti
Estimated[12]
Binocular overlap (published value)
29° (approximate); approximately horizontal plane; eyes in relaxed (resting) position; head in typical posture for the species; alert live birds		Measured[8]
Binocular field, vertical extent
180° (approximate); approximately horizontal plane; eyes in relaxed (resting) position; head in typical posture for the species; alert live birds		Measured[8]
Field of one eye
180° (approximate); approximately horizontal plane; eyes in relaxed (resting) position; head in typical posture for the species; alert live birds		Measured[8]
Binocular field, widest at any elevation
29°; maximum binocular overlap (widest frontal binocular sector at any elevation); maximum binocular overlap (compiled)		Measured[13]
Field of one eye
127°; medium (air / water) as stated; horizontal plane in the plane of the optic axes; in water; fundus reflex		Measured[14]
Blind area behind the head (published value)
70°; medium (air / water) as stated; horizontal plane in the plane of the optic axes; in water; fundus reflex		Measured[14]
Blind area in front
36°; medium (air / water) as stated; horizontal plane in the plane of the optic axes; in water; binocular printed −36 (footnote: a 36 deg blind area to the front)		Measured[14]
Blind area behind the head (published value)
14°; medium (air / water) as stated; horizontal plane in the plane of the optic axes; in air; fundus reflex		Measured[14]
Field of one eye
183°; medium (air / water) as stated; horizontal plane in the plane of the optic axes; in air; fundus reflex		Measured[14]
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[15][16][17]Number of foveas: 1 Measured[18]
Fovea type: fovea Measured[18]
Fovea type
single central fovea (displaced dorso-temporally from retinal centre)		Group default[15][16][17]
Night visionActivity pattern
diurnal
mode of 3 rows (of 3 rows): diurnal; not_nocturnal; photopic
Measured (not re-verified)[19][20][21]Activity pattern: diurnal Measured (not re-verified)[22][23][24][1][25][26][20][21]
Pupil shape: vertical Group default[27][28]
Reflective layer (tapetum): no Measured[29]
Rods vs cones: cone-dominated Derived[22][23][24][1][25][26][20][21]
Night sensitivity (optical, against people): S = 0.93 µm² sr, 1 times people (log10 ratio 0) Derived[30]
Rods vs cones
cone-dominated
nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated
Derived[19][20][21]
Motion (flicker fusion)Flicker fusion frequency
88.5 Hz
median of 17 relatives in class Aves: Bubo virginianus, Melopsittacus undulatus, Passer domesticus, Taeniopygia guttata, Columba livia, Calypte anna
Group default[31][32][33][34][35]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. Kirwan
  3. Müller et al. 2009
  4. Thermal Activation and Photoactivation of Visual… 2004
  5. Caves et al. 2018
  6. Kirk et al. 2004
  7. Veilleux et al. 2014
  8. Martin et al. 1999
  9. Heesy 2004
  10. Heffner et al. 1992
  11. Campbell & Green 1965
  12. Hadden & Zhang 2023
  13. Troscianko et al. 2012
  14. Hadden et al. 2023
  15. Moore et al. 2017
  16. Potier et al. 2017
  17. Rodrigues et al. 2026
  18. Kopania et al. 2025
  19. Wilman et al. 2014
  20. Schmitz et al. 2011
  21. Moura et al. 2024
  22. Anderson et al. 2017
  23. Borges et al. 2018
  24. Wilman et al. 2014
  25. Maor et al. 2017
  26. Jones et al. 2009
  27. Banks et al. 2015
  28. Cervino et al. 2021
  29. Guareschi et al. 2025
  30. Brauburger et al. 2026
  31. Boström et al. 2016
  32. Haarlem et al. 2026
  33. Healy et al. 2013
  34. Inger et al. 2014
  35. 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.