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Euphausiid shrimp vision: the science and the numbers

Stylocheiron maximum · order Euphausiacea · Crustaceans: all the numbers

The euphausiid shrimp has one cone type, so no colour vision in daylight.[1] Its sharpest vision resolves 0.42 cycles per degree, against 63.75 for people in this dataset.[6] The euphausiid shrimp stops seeing flicker at 44 Hz, against 60 Hz for people.[24]

See it on your photoBack to How does the euphausiid shrimp (Stylocheiron maximum) see?
  • 1colour receptor classMeasured
  • 0.42cycles per degree (sharpness)Measured
  • 44hertz flicker fusion (motion)Measured

The euphausiid shrimp (Stylocheiron maximum) is a crustacean in the order Euphausiacea. Its eyes belong to the vision type Crustacean (mantis shrimp, crab): compound eyes whose colour classes, ultraviolet and polarisation vision vary widely between species. Measured in this species: colour, sharpness 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 the euphausiid shrimp sees: colour receptors

Euphausiid shrimp colour receptor peaks, 300 to 700 nmEuphausiid shrimp: 1 receptor peak at 474.5 nm; you: 3 at 421.5, 532, 558.4 nm. ultraviolet300400500600700
Euphausiid shrimp: 474.5 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 0.42 cycles per degree: the finest stripe pattern it can tell apart from grey.
  • It stops seeing flicker at 44 Hz, against 60 Hz for people in this dataset, so fast motion looks choppier to it.[25][26]

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 euphausiid shrimp (Stylocheiron maximum) (Stylocheiron maximum), catalogue-v1
DialValueEvidenceSourcesPeople
ColourColour receptors
1 receptor class: 474.5 nm (SWS (blue))
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)[2][3][4][5]
SharpnessAcuity
0.42 cycles per degree
median of 1 compilation rows (method priority rule)
Measured[6]Acuity: 63.75 cycles per degree Measured[7][8]
Angle between facets
1.6°
median of 1 relatives in class Malacostraca: Phronima sedentaria
Group default[9]
Eye type
compound eye
Field of viewNo value in the catalogue.Binocular overlap: 122.5° Measured[10][11]
Total field of view: 200° Measured (not re-verified)[12]
Blind area behind the head: 160° Derived[12]
Eye placement: frontal Derived[10][11]
Sharp zones (foveas)No value in the catalogue.Number of foveas: 1 Measured[13]
Fovea type: fovea Measured[13]
Night visionActivity pattern
nocturnal
group default: mode of tier-A values in vision type the "Crustacean (mantis shrimp, crab)" type within phylum Arthropoda (1 species: Ligia exotica)
Group default[2]Activity pattern: diurnal Measured (not re-verified)[14][15][16][2][17][18][19][20]
Pupil shape: vertical Group default[21][22]
Reflective layer (tapetum): no Measured[23]
Rods vs cones: cone-dominated Derived[14][15][16][2][17][18][19][20]
Rods vs cones
no rods (invertebrate photoreceptors)		Group default[2]
Motion (flicker fusion)Flicker fusion frequency
44 Hz
median of 1 bright-light rows (behavioural/whole-eye ERG rows; all rows: [44.0]); cff_hz: dim-light rows (bright-light rows used) set aside (labelled alternative: 34.0, 36.0, 40.0)
Measured[24]Flicker fusion frequency: 60 Hz Measured[25][26]

All crustaceans side by side: Crustaceans: every measurement. Method: how we know what animals see.

Sources

  1. Porter
  2. Longcore 2023
  3. Kirwan
  4. Müller et al. 2009
  5. Thermal Activation and Photoactivation of Visual… 2004
  6. Feller et al. 2021
  7. Kirk et al. 2004
  8. Veilleux et al. 2014
  9. Bagheri et al. 2022
  10. Heesy 2004
  11. Heffner et al. 1992
  12. Campbell & Green 1965
  13. Kopania et al. 2025
  14. Anderson et al. 2017
  15. Borges et al. 2018
  16. Wilman et al. 2014
  17. Maor et al. 2017
  18. Jones et al. 2009
  19. Schmitz et al. 2011
  20. Moura et al. 2024
  21. Banks et al. 2015
  22. Cervino et al. 2021
  23. Guareschi et al. 2025
  24. Lafitte et al. 2022
  25. Healy et al. 2013
  26. 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.