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Pig vision: the science and the numbers

Sus scrofa · order Artiodactyla · Mammals: all the numbers

Pigs have 2 colour receptor classes (439 and 556 nm): mainly blues and yellows; reds and greens look alike.[1] Their sharpest vision resolves 9.92 cycles per degree, against 63.75 for people in this dataset.[5] Both eyes see the same 47° in front of them.[7] Pigs stop seeing flicker at 60 Hz, against 60 Hz for people.[22]

See it on your photoBack to How do pigs see?
  • 2colour receptor classesMeasured
  • 9.92cycles per degree (sharpness)Measured
  • 47°seen by both eyesMeasured
  • 60hertz flicker fusion (motion)Measured

The pig (Sus scrofa) is a mammal in the order Artiodactyla. Its eyes belong to the vision type Grazing ungulate panorama: two cone types, a horizontal band of sharp vision and a near-panoramic field with a blind area behind the head. Measured in this species: colour, sharpness, field of view, foveas, night vision and motion (flicker fusion). 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 pigs see: colour receptors

Pig colour receptor peaks, 300 to 700 nmPig: 2 receptor peaks at 439, 556 nm; you: 3 at 421.5, 532, 558.4 nm. ultraviolet300400500600700
Pig: 439, 556 nmPeople: 421.5, 532, 558.4 nmWavelength in nanometres

What stands out

  • It has two colour receptor classes (a dichromat): reds and greens fall on one axis, as in red-green colour blindness in people.
  • Its sharpest vision resolves 9.92 cycles per degree: the finest stripe pattern it can tell apart from grey.
  • Both eyes see the same 47° in front of it (binocular overlap), where depth is judged best.
  • It stops seeing flicker at 60 Hz, against 60 Hz for people in this dataset, so fast motion looks about the same.[23][24]
  • Activity pattern: nocturnal.

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 pig (Sus scrofa), catalogue-v1
DialValueEvidenceSourcesPeople
ColourColour receptors
2 receptor classes: 439 nm (VS/SWS (violet)), 556 nm (LWS (long))
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)[1][2][3][4]
SharpnessAcuity
9.92 cycles per degree
median of 1 anatomical-ganglion rows (method priority rule)
Measured[5]Acuity: 63.75 cycles per degree Measured[6][5]
Field of viewBinocular overlap
47°
median of 1 rows (eyes-at-rest rows preferred)
Measured[7]Binocular overlap: 122.5° Measured[8][7]
Total field of view: 200° Measured (not re-verified)[9]
Blind area behind the head: 160° Derived[9]
Eye placement: frontal Derived[8][7]
Total field of view
350°
group default: median total field of vision type the "Grazing ungulate panorama" type within phylum Chordata in species-v1: Equus caballus
Group default[10]
Sharp zones (foveas)Number of foveas
0
fovea_present / area_centralis_type (retinal topography; count 1 = fovea present, 0 = none)
Measured[11]Number of foveas: 1 Measured[11]
Fovea type: fovea Measured[11]
Fovea type
area centralis, horizontal streak		Measured[11]
Night visionActivity pattern
nocturnal
mode of 9 rows (of 10 rows): cathemeral; cathemeral (polyphasic); diurnal; diurnal/crepuscular; mixed (nocturnal/crepuscular, cathemeral, crepuscular or diurnal/crepuscular); nocturnal; nocturnal/crepuscular; scotopic
Measured (not re-verified)[12][13][14][15][1][16][17][18][19]Activity pattern: diurnal Measured (not re-verified)[12][14][15][1][16][17][18][19]
Pupil shape: vertical Group default[13][20]
Reflective layer (tapetum): no Measured[21]
Rods vs cones: cone-dominated Derived[12][14][15][1][16][17][18][19]
Rods vs cones
rod-dominated
nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated
Derived[12][13][14][15][1][16][17][18][19]
Motion (flicker fusion)Flicker fusion frequency
60 Hz
median of 1 rows (no bright-light flag) (behavioural/whole-eye ERG rows; all rows: [60.0])
Measured[22]Flicker fusion frequency: 60 Hz Measured[23][24]

All mammals side by side: Mammals: 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. Veilleux et al. 2014
  6. Kirk et al. 2004
  7. Heffner et al. 1992
  8. Heesy 2004
  9. Campbell & Green 1965
  10. Timney & Keil 1992
  11. Kopania et al. 2025
  12. Anderson et al. 2017
  13. Banks et al. 2015
  14. Borges et al. 2018
  15. Wilman et al. 2014
  16. Maor et al. 2017
  17. Jones et al. 2009
  18. Schmitz et al. 2011
  19. Moura et al. 2024
  20. Cervino et al. 2021
  21. Guareschi et al. 2025
  22. Haarlem et al. 2026
  23. Healy et al. 2013
  24. 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.