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Fat-tailed dunnart vision: the science and the numbers

Sminthopsis crassicaudata · order Dasyuromorphia · Mammals: all the numbers

The fat-tailed dunnart has 3 colour receptor classes (363, 509 and 535 nm), one of them in the ultraviolet.[1] Its sharpest vision resolves 2.38 cycles per degree, against 63.75 for people in this dataset.[6][7] Both eyes see the same 140° in front of it.[9]

See it on your photoBack to How does the fat-tailed dunnart see?
  • 3colour receptor classesMeasured*
  • 2.38cycles per degree (sharpness)Measured
  • 140°seen by both eyesMeasured

The fat-tailed dunnart (Sminthopsis crassicaudata) is a mammal in the order Dasyuromorphia. 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, sharpness, field of view 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.

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 fat-tailed dunnart sees: colour receptors

Fat-tailed dunnart colour receptor peaks, 300 to 700 nmFat-tailed dunnart: 3 receptor peaks at 363, 509, 535 nm; you: 3 at 421.5, 532, 558.4 nm. ultraviolet300400500600700
Fat-tailed dunnart: 363, 509, 535 nmPeople: 421.5, 532, 558.4 nmWavelength in nanometres

What stands out

  • It has three colour receptor classes, like most people, but one of them sees ultraviolet.
  • Its sharpest vision resolves 2.38 cycles per degree: the finest stripe pattern it can tell apart from grey.
  • Both eyes see the same 140° in front of it (binocular overlap), where depth is judged best.
  • 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 fat-tailed dunnart (Sminthopsis crassicaudata), catalogue-v1
DialValueEvidenceSourcesPeople
ColourColour receptors
3 receptor classes: 363 nm (UVS), 509 nm (MWS (green)), 535 nm (MWS (green))
measured in this species
Measured (not re-verified)[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)[2][3][4][5]
Ultraviolet
yes: at least one receptor peaks in the ultraviolet		Measured (not re-verified)
SharpnessAcuity
2.38 cycles per degree
median of 2 behavioural rows (method priority rule)
Measured[6][7]Acuity: 63.75 cycles per degree Measured[7][8]
Field of viewBinocular overlap
140°
median of 1 rows (eyes-at-rest rows preferred)
Measured[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
median of 80 relatives in class Mammalia: Canis lupus, Vulpes lagopus, Acinonyx jubatus, Felis catus, Crocuta crocuta, Enhydra lutris
Group default[12]Number of foveas: 1 Measured[12]
Fovea type: fovea Measured[12]
Fovea type
area centralis		Group default[12]
Night visionActivity pattern
nocturnal
mode of 6 rows (of 7 rows): cathemeral; mixed (nocturnal/crepuscular, cathemeral, crepuscular or diurnal/crepuscular); nocturnal; nocturnal/crepuscular
Measured (not re-verified)[13][14][15][16][17][8]Activity pattern: diurnal Measured (not re-verified)[18][13][14][2][15][16][19][17]
Pupil shape: vertical Group default[20][21]
Reflective layer (tapetum): no Measured[22]
Rods vs cones: cone-dominated Derived[18][13][14][2][15][16][19][17]
Rods vs cones
rod-dominated
nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated
Derived[13][14][15][16][17][8]
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[23][24][25][26]Flicker fusion frequency: 60 Hz Measured[24][25]

All mammals side by side: Mammals: every measurement. Method: how we know what animals see.

Sources

  1. Arrese et al. 2002; Cowing et al. 2008
  2. Longcore 2023
  3. Kirwan
  4. Müller et al. 2009
  5. Thermal Activation and Photoactivation of Visual… 2004
  6. Caves et al. 2024
  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. Borges et al. 2018
  14. Wilman et al. 2014
  15. Maor et al. 2017
  16. Jones et al. 2009
  17. Moura et al. 2024
  18. Anderson et al. 2017
  19. Schmitz et al. 2011
  20. Banks et al. 2015
  21. Cervino et al. 2021
  22. Guareschi et al. 2025
  23. Haarlem et al. 2026
  24. Healy et al. 2013
  25. Inger et al. 2014
  26. 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.