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Black flying fox vision: the science and the numbers

Pteropus alecto · order Chiroptera · Mammals: all the numbers

Its sharpest vision resolves 3.73 cycles per degree, against 63.75 for people in this dataset.[6] Its activity pattern is nocturnal.[6][13][14][15][16]

  • 3.73cycles per degree (sharpness)Measured

The black flying fox (Pteropus alecto) is a mammal in the order Chiroptera. 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: 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 black flying fox sees: colour receptors

Black flying fox colour receptor peaks, 300 to 700 nmBlack flying fox: 2 receptor peaks at 358, 553 nm; you: 3 at 421.5, 532, 558.4 nm. ultraviolet300400500600700
Black flying fox: 358, 553 nmPeople: 421.5, 532, 558.4 nmWavelength in nanometres

What stands out

  • Its sharpest vision resolves 3.73 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 black flying fox (Pteropus alecto), catalogue-v1
DialValueEvidenceSourcesPeople
ColourColour receptors
2 receptor classes: 358 nm (UVS), 553 nm (LWS (long))
receptor set of nearest measured relative Pteropus dasymallus (same genus Pteropus)
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]
Ultraviolet
yes: at least one receptor peaks in the ultraviolet
Estimated
SharpnessAcuity
3.73 cycles per degree
median of 1 compilation rows (method priority rule)
Measured[6]Acuity: 63.75 cycles per degree Measured[7][8]
Field of viewBinocular overlap
108°
median of 1 relatives in genus Pteropus: Pteropus poliocephalus
Estimated[9]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]
Sharp zones (foveas)Number of foveas
0
fovea_present / area_centralis_type (retinal topography; count 1 = fovea present, 0 = none)
Measured[12]Number of foveas: 1 Measured[12]
Fovea type: fovea Measured[12]
Fovea type
area centralis
Measured[12]
Night visionActivity pattern
nocturnal
mode of 7 rows (of 7 rows): nocturnal; scotopic
Measured (not re-verified)[6][13][14][15][16]Activity pattern: diurnal Measured (not re-verified)[17][6][13][1][14][18][15][16]
Pupil shape: vertical Group default[19][20]
Reflective layer (tapetum): no Measured[21]
Rods vs cones: cone-dominated Derived[17][6][13][1][14][18][15][16]
Rods vs cones
rod-dominated
nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated
Derived[6][13][14][15][16]
Motion (flicker fusion)Flicker fusion frequency
60 Hz
median of 21 relatives in class Mammalia: Rattus norvegicus, Cavia porcellus, Mus musculus, Felis catus, Macaca mulatta, Macaca nemestrina
Group default[22][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. Borges et al. 2018
  7. Kirk et al. 2004
  8. Veilleux et al. 2014
  9. Heesy 2004
  10. Heffner et al. 1992
  11. Campbell & Green 1965
  12. Kopania et al. 2025
  13. Wilman et al. 2014
  14. Maor et al. 2017
  15. Schmitz et al. 2011
  16. Moura et al. 2024
  17. Anderson et al. 2017
  18. Jones et al. 2009
  19. Banks et al. 2015
  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
  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.