Capybara vision: the science and the numbers
Hydrochoerus hydrochaeris · order Rodentia · Mammals: all the numbers
Its sharpest vision resolves 5.8 cycles per degree, against 63.75 for people in this dataset.[6] Its activity pattern is cathemeral.[14][15][16][17][18][19]
- 5.8cycles per degree (sharpness)Measured
The capybara (Hydrochoerus hydrochaeris) is a mammal in the order Rodentia. 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: 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 capybara sees: colour receptors
What stands out
- Its sharpest vision resolves 5.8 cycles per degree: the finest stripe pattern it can tell apart from grey.
- 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: 400 nm (VS/SWS (violet)), 530 nm (MWS (green)) receptor set of nearest measured relative Cavia porcellus (same family Caviidae) | 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] |
| Sharpness | Acuity 5.8 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 view | Binocular overlap 52° median of 15 relatives in order Rodentia: Octodon degus, Octodon lunatus, Rattus rattus, Mus musculus, Mesocricetus auratus, Sciurus carolinensis | Group default | [8][9][10][11] | Binocular overlap: 122.5° Measured[8][9] Total field of view: 200° Measured (not re-verified)[12] Blind area behind the head: 160° Derived[12] Eye placement: frontal Derived[8][9] |
| Sharp zones (foveas) | Number of foveas 0 fovea_present / area_centralis_type (retinal topography; count 1 = fovea present, 0 = none) | Measured | [13] | Number of foveas: 1 Measured[13] Fovea type: fovea Measured[13] |
| Fovea type horizontal streak | Measured | [13] | ||
| Night vision | Activity pattern cathemeral tie ['cathemeral', 'diurnal'] broken by species-level studies (round-3 tie-break rule 2) (of 10 rows): cathemeral; crepuscular; diurnal; mesopic; mixed (nocturnal/crepuscular, cathemeral, crepuscular or… | Measured (not re-verified) | [14][15][16][17][18][19] | Activity pattern: diurnal Measured (not re-verified)[14][20][15][1][16][17][18][19] Pupil shape: vertical Group default[21][22] Reflective layer (tapetum): no Measured[23] Rods vs cones: cone-dominated Derived[14][20][15][1][16][17][18][19] |
| Rods vs cones mixed nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated | Derived | [14][15][16][17][18][19] | ||
| Motion (flicker fusion) | Flicker fusion frequency 47.5 Hz median of 1 relatives in family Caviidae: Cavia porcellus | Estimated | [24] | Flicker fusion frequency: 60 Hz Measured[25][26] |
All mammals side by side: Mammals: every measurement. Method: how we know what animals see.
Sources
- Longcore 2023
- VPOD in-vivo (MSP / single-cell) lambda… 2025
- 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
- Vega-Zuniga et al. 2013
- Vega-Zuniga et al. 2017
- Campbell & Green 1965
- Kopania et al. 2025
- Anderson et al. 2017
- Wilman et al. 2014
- Maor et al. 2017
- Jones et al. 2009
- Schmitz et al. 2011
- Moura et al. 2024
- Borges et al. 2018
- Banks et al. 2015
- Cervino et al. 2021
- Guareschi et al. 2025
- Lafitte et al. 2022
- 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.