How does the bonnethead see?
The bonnethead (Sphyrna tiburo) is a shark or ray in the order Carcharhiniformes. Its eyes belong to the vision type Shark, ray and warm-eyed ocean predator.
Measured in this species: colour and motion (flicker fusion). Measured colour or sharpness: a measured receptor set or acuity in this species; other dials come from relatives or group defaults. Every value below carries its evidence level and sources; nothing is typed by hand.
What stands out
- It has one receptor class for colour, so it sees brightness but no hue.
- Its sharpest vision resolves 6.72 cycles per degree: the finest stripe pattern it can tell apart from grey.
- It stops seeing flicker at 31 Hz, against 60 Hz for people in this dataset, so fast motion looks choppier to it.[4][5]
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.
| Dial | Value | Evidence | Sources |
|---|---|---|---|
| Colour | Colour receptors 1 receptor class: 483 nm (MWS (green)) measured in this species | Measured (not re-verified) | [1] |
| Sharpness | Acuity 6.72 cycles per degree median of 3 relatives in genus Sphyrna: Sphyrna lewini, Sphyrna mokarran, Sphyrna zygaena | Estimated | [2] |
| Field of view | No value in the catalogue. | ||
| Sharp zones (foveas) | No value in the catalogue. | ||
| Night vision | No value in the catalogue. | ||
| Motion (flicker fusion) | Flicker fusion frequency 31 Hz median of 1 bright-light rows (behavioural/whole-eye ERG rows; all rows: [31.0]) | Measured | [3] |
Related animals
- Scalloped hammerhead shark same vision type
- Blacknose shark same vision type
- Blacktip reef shark same vision type
- Bull shark same vision type
- Lemon shark same vision type
- Sandbar shark same vision type
More sharks and rays: all sharks and rays with measured vision data.
Sources
- Murphy MJ, Westerman EL. 2022. Evolutionary history limits species' ability to match colour sensitivity to available habitat light. Proc R Soc B 289:20220612. Electronic supplementary Table S1. doi.org/10.1098/rspb.2022.0612
- Claes JM et al. 2014. Photon hunting in the twilight zone: visual features of mesopelagic bioluminescent sharks. PLoS ONE 9:e104213, Dataset S1. doi.org/10.1371/journal.pone.0104213
- Lafitte A, Sordello R, Legrand M, Nicolas V, Obein G, Reyjol Y. 2022. A flashing light may not be that flashy: A systematic review on critical fusion frequencies. PLoS ONE 17(12): e0279718. S10 File (CFF database). doi.org/10.1371/journal.pone.0279718
- Healy K, McNally L, Ruxton GD, Cooper N, Jackson AL. 2013. Metabolic rate and body size are linked with perception of temporal information. Animal Behaviour 86:685-696. Table 1. doi.org/10.1016/j.anbehav.2013.06.018
- Inger R, Bennie J, Davies TW, Gaston KJ. 2014. Potential biological and ecological effects of flickering artificial light. PLoS ONE 9(5): e98631. Table 3. doi.org/10.1371/journal.pone.0098631
Every value cites its sources (all sources). Data: catalogue-v1, built 2026-09-29. Accuracy notes: how accurate is this?