How does the gray hermit crab see?
The gray hermit crab (Pagurus pollicaris) is a crustacean in the order Decapoda. Its eyes belong to the vision type Crustacean (mantis shrimp, crab).
Measured in this species: colour. 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.
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What stands out
- It has one receptor class for colour, so it sees brightness but no hue.
- Its sharpest vision resolves 0.15 cycles per degree: the finest stripe pattern it can tell apart from grey.
- It stops seeing flicker at 56 Hz, against 60 Hz for people in this dataset, so fast motion looks about the same.[8][9]
- 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.
| Dial | Value | Evidence | Sources |
|---|---|---|---|
| Colour | Colour receptors 1 receptor class: 515.5 nm (MWS (green)) measured in this species | Measured | [1] |
| Sharpness | Acuity 0.15 cycles per degree median of 94 relatives in order Decapoda: Anchistus custos, Ancylomenes holthuisi, Ancylomenes pedersoni, Ancylomenes venustus, Austruca lactea, Brucecaris tenuis | Group default | [2][3][4] |
| Angle between facets 1.6° median of 1 relatives in class Malacostraca: Phronima sedentaria | Group default | [5] | |
| Eye type compound eye | |||
| Field of view | No value in the catalogue. | ||
| Sharp zones (foveas) | No value in the catalogue. | ||
| Night vision | Activity pattern nocturnal group default: mode of tier-A values in vision type V27 within phylum Arthropoda (1 species: Ligia exotica) | Group default | [6] |
| Rods vs cones no rods (invertebrate photoreceptors) | Group default | [6] | |
| Motion (flicker fusion) | Flicker fusion frequency 56 Hz median of 1 relatives in genus Pagurus: Pagurus bernhardus | Estimated | [7] |
Other senses
- polarisation vision: optional overlay of degree/angle of linear polarisation (Group default)
Related animals
- Caridean shrimp same vision type
- American lobster same vision type
- Atlantic marsh fiddler same vision type
- Blue crab same vision type
- Crab same vision type
- Deep sea shrimp same vision type
More crustaceans: all crustaceans with measured vision data.
Sources
- Porter ML. Crustacean photoreceptor lambda max compilation, Table 1-1 (dissertation, "Porter_2005" in VPOD); extracted from PDF by VPOD with tabula. github.com/VisualPhysiologyDB/visual-physiology-opsin-db
- AndrewPMeade/FabricTools, sciphy/data_utils/datasets/Arthropod.CompoundEyes.csv (acuity, body length, light, media for 281 arthropods; columns match Feller et al. 2021 Arthropod Struct Dev 60:101002). github.com/AndrewPMeade/FabricTools
- Feller KD, Sharkey CR, McDuffee-Altekruse A, Bracken-Grissom HD, Lord NP, Porter ML, Schweikert LE 2021. Surf and turf vision: patterns and predictors of visual acuity in compound eye evolution. Arthropod Structure & Development 60:101002. doi.org/10.1016/j.asd.2020.101002
- Schweikert L, Davis A, Johnsen S et al. 2020. Visual perception of light organ patterns in deep‐sea shrimps and implications for conspecific recognition. Ecology and Evolution. doi.org/10.1002/ece3.6643
- Bagheri Z, Jessop A, Partridge J et al. 2022. A new computational model illuminates the extraordinary eyes of Phronima. PLOS Computational Biology. doi.org/10.1371/journal.pcbi.1010545
- Longcore T. 2023. A compendium of photopigment peak sensitivities and visual spectral response curves of terrestrial wildlife to guide design of outdoor nighttime lighting. Basic Appl Ecol 73:40-50. doi:10.1016/j.baae.2023.09.002. doi.org/10.5281/zenodo.8432720
- Haarlem CS, Hynes C, Jackson AL, Mitchell KJ, O'Connell RG, Healy K. 2026. Pace of ecology drives the tempo of visual perception across the animal kingdom. Nature Ecology & Evolution (doi:10.1038/s41559-026-02994-7). Figshare dataset 10.6084/m9.figshare.30556475. doi.org/10.6084/m9.figshare.30556475
- 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?