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Ground squirrel vision: the science and the numbers

Callospermophilus lateralis · order Rodentia · Mammals: all the numbers

The ground squirrel has 2 colour receptor classes (435 and 520 nm): mainly blues and yellows; reds and greens look alike.[1] The ground squirrel stops seeing flicker at 114 Hz, against 60 Hz for people.[21][22]

  • 2colour receptor classesMeasured
  • 114hertz flicker fusion (motion)Measured

The ground squirrel (Callospermophilus lateralis) is a mammal in the order Rodentia. Its eyes belong to the vision type Small prey mammal (UV): two or three cone types, often including ultraviolet, low sharpness and a near-panoramic field. Measured in this species: colour, 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.

What the ground squirrel sees: colour receptors

Ground squirrel colour receptor peaks, 300 to 700 nmGround squirrel: 2 receptor peaks at 435, 520 nm; you: 3 at 421.5, 532, 558.4 nm. ultraviolet300400500600700
Ground squirrel: 435, 520 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.
  • It stops seeing flicker at 114 Hz, against 60 Hz for people in this dataset, so fast motion looks about 1.9 times slower to it.[21][22]
  • 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 ground squirrel (Callospermophilus lateralis), catalogue-v1
DialValueEvidenceSourcesPeople
ColourColour receptors
2 receptor classes: 435 nm (VS/SWS (violet)), 520 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)[1][2][3][4]
SharpnessAcuity
3.9 cycles per degree
median of 5 relatives in family Sciuridae: Sciurus carolinensis, Sciurus niger, Otospermophilus beecheyi, Sciurus griseus, Ictidomys tridecemlineatus
Estimated[5][6][7]Acuity: 63.75 cycles per degree Measured[6][7]
Field of viewBinocular overlap
60°
median of 1 relatives in family Sciuridae: Sciurus carolinensis
Estimated[8]Binocular overlap: 122.5° Measured[8][9]
Total field of view: 200° Measured (not re-verified)[10]
Blind area behind the head: 160° Derived[10]
Eye placement: frontal Derived[8][9]
Sharp zones (foveas)Number of foveas
0
median of 2 relatives in family Sciuridae: Ictidomys tridecemlineatus, Otospermophilus beecheyi
Estimated[11]Number of foveas: 1 Measured[11]
Fovea type: fovea Measured[11]
Fovea type
horizontal streak
Estimated[11]
Night visionActivity pattern
diurnal
mode of 4 rows (of 4 rows): diurnal
Measured (not re-verified)[12][1][13][14]Activity pattern: diurnal Measured (not re-verified)[15][5][12][1][13][16][17][14]
Pupil shape: vertical Group default[18][19]
Reflective layer (tapetum): no Measured[20]
Rods vs cones: cone-dominated Derived[15][5][12][1][13][16][17][14]
Rods vs cones
cone-dominated
nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated
Derived[12][1][13][14]
Motion (flicker fusion)Flicker fusion frequency
114 Hz
median of 2 bright-light rows (behavioural/whole-eye ERG rows; all rows: [108.0, 120.0])
Measured[21][22]Flicker fusion frequency: 60 Hz Measured[21][22]

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