Sheep vision: the science and the numbers
Ovis aries · order Artiodactyla · Mammals: all the numbers
Sheep have 2 colour receptor classes (446 and 552 nm): mainly blues and yellows; reds and greens look alike.[1] Their sharpest vision resolves 5.61 cycles per degree, against 63.75 for people in this dataset.[5] Both eyes see the same 61.7° in front of them.[7] Sheep stop seeing flicker at 60 Hz, against 60 Hz for people.[22]
- 2colour receptor classesMeasured
- 5.61cycles per degree (sharpness)Measured
- 61.7°seen by both eyesMeasured
- 60hertz flicker fusion (motion)Measured*
The sheep (Ovis aries) is a mammal in the order Artiodactyla. Its eyes belong to the vision type Grazing ungulate panorama: two cone types, a horizontal band of sharp vision and a near-panoramic field with a blind area behind the head. Measured in this species: colour, sharpness, field of view, foveas, 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 sheep see: colour receptors
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.
- Its sharpest vision resolves 5.61 cycles per degree: the finest stripe pattern it can tell apart from grey.
- Both eyes see the same 61.7° in front of it (binocular overlap), where depth is judged best.
- It stops seeing flicker at 60 Hz, against 60 Hz for people in this dataset, so fast motion looks about the same.[23][24]
- Activity pattern: cathemeral.
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.
| Dial | Value | Evidence | Sources | People |
|---|---|---|---|---|
| Colour | Colour receptors 2 receptor classes: 446 nm (SWS (blue)), 552 nm (LWS (long)) 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] |
| Sharpness | Acuity 5.61 cycles per degree median of 1 behavioural rows (method priority rule) | Measured | [5] | Acuity: 63.75 cycles per degree Measured[6][5] |
| Field of view | Binocular overlap 61.7° median of 1 rows (eyes-at-rest rows preferred) | Measured | [7] | Binocular overlap: 122.5° Measured[7][8] Total field of view: 200° Measured (not re-verified)[9] Blind area behind the head: 160° Derived[9] Eye placement: frontal Derived[7][8] |
| Total field of view 350° group default: median total field of vision type the "Grazing ungulate panorama" type within phylum Chordata in species-v1: Equus caballus | Group default | [10] | ||
| Sharp zones (foveas) | Number of foveas 0 fovea_present / area_centralis_type (retinal topography; count 1 = fovea present, 0 = none) | Measured | [11] | Number of foveas: 1 Measured[11] Fovea type: fovea Measured[11] |
| Fovea type anakatabatic area, area centralis, horizontal streak | Measured | [11] | ||
| Night vision | Activity pattern cathemeral tie ['cathemeral', 'diurnal'] broken by the broader category (round-3 tie-break rule 3: cathemeral > crepuscular > nocturnal > diurnal) (of 9 rows): cathemeral; diurnal; mesopic; nocturnal; photopic | Measured (not re-verified) | [12][13][1][14][15][16][5] | Activity pattern: diurnal Measured (not re-verified)[17][12][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][12][13][1][14][18][15][16] |
| Rods vs cones mixed nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated | Derived | [12][13][1][14][15][16][5] | ||
| Motion (flicker fusion) | Flicker fusion frequency 60 Hz median of 1 rows (no bright-light flag) (behavioural/whole-eye ERG rows; all rows: [60.0]) | Measured (not re-verified) | [22] | Flicker fusion frequency: 60 Hz Measured[23][24] |
All mammals side by side: Mammals: every measurement. Method: how we know what animals see.
Sources
- Longcore 2023
- Kirwan
- Müller et al. 2009
- Thermal Activation and Photoactivation of Visual… 2004
- Veilleux et al. 2014
- Kirk et al. 2004
- Heesy 2004
- Heffner et al. 1992
- Campbell & Green 1965
- Timney & Keil 1992
- Kopania et al. 2025
- Borges et al. 2018
- Wilman et al. 2014
- Maor et al. 2017
- Schmitz et al. 2011
- Moura et al. 2024
- Anderson et al. 2017
- Jones et al. 2009
- Banks et al. 2015
- Cervino et al. 2021
- Guareschi et al. 2025
- Haarlem et al. 2026
- Healy et al. 2013
- 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.