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Philippine tarsier vision: the science and the numbers

Carlito syrichta · order Primates · Mammals: all the numbers

The Philippine tarsier has one cone type, so no colour vision in daylight.[1][2] Its sharpest vision resolves 8.89 cycles per degree, against 63.75 for people in this dataset.[6]

  • 1colour receptor classMeasured
  • 8.89cycles per degree (sharpness)Measured

The Philippine tarsier (Carlito syrichta) is a mammal in the order Primates. Its eyes belong to the vision type Nocturnal mammal (primate, bat): rod-dominated eyes with few working cone types and low sharpness. 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.

What the Philippine tarsier sees: colour receptors

Philippine tarsier colour receptor peaks, 300 to 700 nmPhilippine tarsier: 1 receptor peak at 558 nm; you: 3 at 421.5, 532, 558.4 nm. ultraviolet300400500600700
Philippine tarsier: 558 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 8.89 cycles per degree: the finest stripe pattern it can tell apart from grey.
  • 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 Philippine tarsier (Carlito syrichta), catalogue-v1
DialValueEvidenceSourcesPeople
ColourColour receptors
1 receptor class: 558 nm (LWS (long))
measured in this species
Measured[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
8.89 cycles per degree
median of 1 anatomical-ganglion rows (method priority rule)
Measured[6]Acuity: 63.75 cycles per degree Measured[7][6]
Field of viewBinocular overlap
127°
median of 1 relatives in family Tarsiidae: Cephalopachus bancanus
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]
Total field of view
200°
median species-v1 total field of order Primates: Homo sapiens
Group default[10]
Sharp zones (foveas)Number of foveas
1
species-v1.csv text: 1 (central fovea)
Measured (not re-verified)[11]Number of foveas: 1 Measured[12]
Fovea type: fovea Measured[12]
Fovea type
central fovea
Measured (not re-verified)[11]
Night visionActivity pattern
nocturnal
mode of 8 rows (of 8 rows): nocturnal; nocturnal/crepuscular; scotopic
Measured (not re-verified)[13][14][1][15][16][17][18]Activity pattern: diurnal Measured (not re-verified)[19][13][14][1][15][16][17][18]
Pupil shape: vertical Group default[20][21]
Reflective layer (tapetum): no Measured[22]
Rods vs cones: cone-dominated Derived[19][13][14][1][15][16][17][18]
Rods vs cones
rod-dominated
nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated
Derived[13][14][1][15][16][17][18]
Motion (flicker fusion)Flicker fusion frequency
69 Hz
median of 3 relatives in order Primates: Macaca mulatta, Macaca nemestrina, Homo sapiens
Group default[23][24][25]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. VPOD in-vivo (MSP / single-cell) lambda… 2025
  3. Kirwan
  4. Müller et al. 2009
  5. Thermal Activation and Photoactivation of Visual… 2004
  6. Veilleux et al. 2014
  7. Kirk et al. 2004
  8. Heesy 2004
  9. Heffner et al. 1992
  10. Campbell & Green 1965
  11. Hendrickson et al. 2000
  12. Kopania et al. 2025
  13. Borges et al. 2018
  14. Wilman et al. 2014
  15. Maor et al. 2017
  16. Jones et al. 2009
  17. Schmitz et al. 2011
  18. Moura et al. 2024
  19. Anderson et al. 2017
  20. Banks et al. 2015
  21. Cervino et al. 2021
  22. Guareschi et al. 2025
  23. Healy et al. 2013
  24. Inger et al. 2014
  25. 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.