The eye map: sharpness against speed in animal eyes
Visual acuity (how fine a detail an eye resolves) against flicker fusion frequency (how fast a flicker must be before it looks steady) for every species in the catalogue with both values measured: 60 species, people included.
What the map shows
- 60 species have both a measured visual acuity and a measured flicker fusion frequency (evidence A, AU or D); reconstructions are left out.
- People sit at 63.75 cycles per degree and 60 Hz. 0 of the plotted species have sharper eyes, 25 have a higher flicker fusion frequency, and 0 beat people on both.
- Spearman rank correlation between the two values over these 60 species: 0.22 (computed in code from the table below). Sharp eyes and fast eyes are separate abilities: being high on one does not predict the other well.
Method
- Values are the catalogue values for each species: acuity in cycles per degree (behavioural or anatomical estimates, as recorded per source) and flicker fusion in hertz (bright-light values).
- Only values measured in the species itself (A, AU) or derived from measured values (D) are plotted; estimates from relatives are not.
- Both axes use a log scale because the values span more than one power of ten.
- Methods differ between studies, so small gaps between neighbours are not meaningful.
The data
| Animal | Group | Sharpness | Evidence | Flicker fusion | Evidence | Sources |
|---|---|---|---|---|---|---|
| American cockroach Periplaneta americana | Insects | 0.21 cycles/degree | Measured | 42.1 Hz | Measured | Caves et al. 2018; Inger et al. 2014; Lafitte et al. 2022 |
| American yellow perch Perca flavescens | Fish | 3.5 cycles/degree | Measured | 23 Hz | Measured | Caves et al. 2017; Lafitte et al. 2022 |
| Anna's hummingbird Calypte anna | Birds | 6 cycles/degree | Measured | 75 Hz | Measured | Caves et al. 2024; Lafitte et al. 2022 |
| Asian palm weevil Rhynchophorus ferrugineus | Insects | 0.33 cycles/degree | Measured | 100 Hz | Measured | Feller et al. 2021; Haarlem et al. 2026 |
| Brown rat Rattus norvegicus | Mammals | 1.5 cycles/degree | Measured | 51 Hz | Measured | Kirk et al. 2004; Veilleux et al. 2014; Lafitte et al. 2022 |
| Brown-headed cowbird Molothrus ater | Birds | 5.1 cycles/degree | Measured | 114.7 Hz | Measured | Caves et al. 2018; Lafitte et al. 2022 |
| Brownbanded bamboo shark Chiloscyllium punctatum | Fish | 1.8 cycles/degree | Measured | 44 Hz | Measured | Caves et al. 2024; Lafitte et al. 2022 |
| Budgerigar Melopsittacus undulatus | Birds | 14.3 cycles/degree | Measured | 74.7 Hz | Measured | Caves et al. 2024; Healy et al. 2013; Lafitte et al. 2022 |
| Bull ant (Myrmecia gulosa) Myrmecia gulosa | Insects | 0.29 cycles/degree | Measured | 151.6 Hz | Measured | Caves et al. 2018; Haarlem et al. 2026 |
| Bull ant (Myrmecia tarsata) Myrmecia tarsata | Insects | 1.02 cycles/degree | Measured | 162.6 Hz | Measured | Feller et al. 2021; Haarlem et al. 2026 |
| Caridean shrimp Heterocarpus ensifer | Crustaceans | 0.31 cycles/degree | Measured | 16 Hz | Measured | AndrewPMeade/FabricTools, sciphy/data_utils/datas… 2021; Haarlem et al. 2026 |
| Cat Felis catus | Mammals | 8.8 cycles/degree | Measured | 75 Hz | Measured (not re-verified) | Caves et al. 2024; Kirk et al. 2004; Veilleux et al. 2014; Lafitte et al. 2022 |
| Chicken Gallus gallus | Birds | 7 cycles/degree | Measured | 104 Hz | Measured | Caves et al. 2018; Caves et al. 2024; Lafitte et al. 2022 |
| Common brushtail possum Trichosurus vulpecula | Mammals | 4.8 cycles/degree | Measured | 22.4 Hz | Measured | Veilleux et al. 2014; Haarlem et al. 2026 |
| Common eggfly Hypolimnas bolina | Insects | 0.57 cycles/degree | Measured | 182 Hz | Measured | Feller et al. 2021; Lafitte et al. 2022 |
| Common evening brown Melanitis leda | Insects | 0.35 cycles/degree | Measured | 200.9 Hz | Measured | Caves et al. 2018; Lafitte et al. 2022 |
| Common treeshrew Tupaia glis | Mammals | 4.7 cycles/degree | Measured | 90 Hz | Measured | Veilleux et al. 2014; Healy et al. 2013 |
| Copula sivickisi Copula sivickisi | Others | 0.08 cycles/degree | Derived | 2.5 Hz | Measured | Garm et al. 2016 |
| Dog Canis familiaris | Mammals | 8.3 cycles/degree | Measured (not re-verified) | 77.5 Hz | Measured (not re-verified) | Heffner et al. 1992; Healy et al. 2013; Inger et al. 2014 |
| Epaulette shark Hemiscyllium ocellatum | Fish | 2.8 cycles/degree | Measured | 40 Hz | Measured | Claes et al. 2014; Lafitte et al. 2022 |
| Euphausiid shrimp (Euphausia gibboides) Euphausia gibboides | Crustaceans | 0.19 cycles/degree | Measured | 24 Hz | Measured (not re-verified) | Feller et al. 2021; Inger et al. 2014 |
| Euphausiid shrimp (Stylocheiron maximum) Stylocheiron maximum | Crustaceans | 0.42 cycles/degree | Measured | 44 Hz | Measured | Feller et al. 2021; Lafitte et al. 2022 |
| European starling Sturnus vulgaris | Birds | 6.29 cycles/degree | Measured | 100 Hz | Measured | Caves et al. 2018; Healy et al. 2013; Inger et al. 2014 |
| Fruit fly (Drosophila melanogaster) Drosophila melanogaster | Insects | 0.125 cycles/degree | Measured | 57 Hz | Measured | Caves et al. 2018; Lafitte et al. 2022 |
| Goldfish Carassius auratus | Fish | 3 cycles/degree | Measured | 53.6 Hz | Measured | Caves et al. 2017; Healy et al. 2013; Lafitte et al. 2022 |
| Great horned owl Bubo virginianus | Birds | 7.125 cycles/degree | Measured (not re-verified) | 40 Hz | Measured | Caves et al. 2018; Potier et al. 2020; Lafitte et al. 2022 |
| Grey wolf Canis lupus | Mammals | 14.57 cycles/degree | Measured | 84 Hz | Measured | Veilleux et al. 2014; Haarlem et al. 2026 |
| Guppy Poecilia reticulata | Fish | 6.7 cycles/degree | Measured | 67 Hz | Measured | Caves et al. 2017; Inger et al. 2014 |
| Haplochromis sauvagei Haplochromis sauvagei | Fish | 3.1 cycles/degree | Measured | 18 Hz | Measured | Caves et al. 2017; Lafitte et al. 2022 |
| Harris's hawk Parabuteo unicinctus | Birds | 43.7 cycles/degree | Measured | 77.7 Hz | Measured | Caves et al. 2018; Lafitte et al. 2022 |
| House mouse Mus musculus | Mammals | 0.5 cycles/degree | Measured | 41.3 Hz | Measured | Veilleux et al. 2014; Lafitte et al. 2022 |
| House sparrow Passer domesticus | Birds | 4.88 cycles/degree | Measured | 55 Hz | Measured | Caves et al. 2018; Lafitte et al. 2022 |
| Housefly Musca domestica | Insects | 0.2 cycles/degree | Measured | 83.3 Hz | Measured | Caves et al. 2018; Haarlem et al. 2026 |
| Human Homo sapiens | People | 63.75 cycles/degree | Measured | 60 Hz | Measured | Kirk et al. 2004; Veilleux et al. 2014; Healy et al. 2013; Inger et al. 2014 |
| Jack jumper / bull ant Myrmecia pyriformis | Insects | 1.02 cycles/degree | Measured | 73.3 Hz | Measured | AndrewPMeade/FabricTools, sciphy/data_utils/datas… 2021; Haarlem et al. 2026 |
| Japanese rice fish Oryzias latipes | Fish | 0.563 cycles/degree | Measured | 37.2 Hz | Measured | Caves et al. 2017; Lafitte et al. 2022 |
| Little owl Athene noctua | Birds | 6.5 cycles/degree | Measured | 50 Hz | Measured | Potier et al. 2020; Lafitte et al. 2022 |
| Migratory locust Locusta migratoria | Insects | 0.53 cycles/degree | Measured | 65 Hz | Measured | Caves et al. 2018; Inger et al. 2014 |
| Northern tree shrew Tupaia belangeri | Mammals | 2.1 cycles/degree | Measured | 60 Hz | Measured | Caves et al. 2024; Kirk et al. 2004; Inger et al. 2014 |
| Pederson cleaner shrimp Ancylomenes pedersoni | Crustaceans | 0.1 cycles/degree | Measured | 48 Hz | Measured | Feller et al. 2021; Haarlem et al. 2026 |
| Phronima sedentaria Phronima sedentaria | Crustaceans | 0.43 cycles/degree | Measured | 27 Hz | Measured | AndrewPMeade/FabricTools, sciphy/data_utils/datas… 2021; Lafitte et al. 2022 |
| Pig Sus scrofa | Mammals | 9.92 cycles/degree | Measured | 60 Hz | Measured | Veilleux et al. 2014; Haarlem et al. 2026 |
| Port jackson shark Heterodontus portusjacksoni | Fish | 3.125 cycles/degree | Measured | 28 Hz | Measured | Caves et al. 2023; Lafitte et al. 2022 |
| Purple-winged mantis Tenodera australasiae | Insects | 0.32 cycles/degree | Measured | 55.3 Hz | Measured | Caves et al. 2018; Haarlem et al. 2026 |
| Rabbit Oryctolagus cuniculus | Mammals | 2.625 cycles/degree | Measured | 30 Hz | Measured | Kirk et al. 2004; Veilleux et al. 2014; Haarlem et al. 2026 |
| Rainbow trout Oncorhynchus mykiss | Fish | 4.29 cycles/degree | Measured | 27.1 Hz | Measured | Caves et al. 2017; Healy et al. 2013; Lafitte et al. 2022 |
| Rhesus macaque Macaca mulatta | Mammals | 51.75 cycles/degree | Measured | 78 Hz | Measured | Kirk et al. 2004; Veilleux et al. 2014; Healy et al. 2013; Inger et al. 2014 |
| Rock pigeon Columba livia | Birds | 14 cycles/degree | Measured | 88.5 Hz | Measured | Caves et al. 2018; Caves et al. 2024; Healy et al. 2013; Lafitte et al. 2022 |
| Sandbar shark Carcharhinus plumbeus | Fish | 8.9 cycles/degree | Measured | 54 Hz | Measured (not re-verified) | Claes et al. 2014; Horodysky et al. 2013 |
| Scalloped hammerhead shark Sphyrna lewini | Fish | 6.89 cycles/degree | Measured | 27.3 Hz | Measured | Claes et al. 2014; Lafitte et al. 2022 |
| Sheep Ovis aries | Mammals | 5.61 cycles/degree | Measured | 60 Hz | Measured (not re-verified) | Veilleux et al. 2014; Haarlem et al. 2026 |
| Smallspotted catshark Scyliorhinus canicula | Fish | 3.98 cycles/degree | Measured | 3.2 Hz | Measured | Claes et al. 2014; Lafitte et al. 2022 |
| Southern pig-tailed macaque Macaca nemestrina | Mammals | 46 cycles/degree | Measured | 69 Hz | Measured | Veilleux et al. 2014; Lafitte et al. 2022 |
| Stick insect Carausius morosus | Insects | 0.07 cycles/degree | Measured | 40 Hz | Measured | Caves et al. 2018; Haarlem et al. 2026 |
| Tiger shark Galeocerdo cuvier | Fish | 6.25 cycles/degree | Measured | 38 Hz | Measured | Caves et al. 2023; Haarlem et al. 2026 |
| Tsetse fly (Glossina pallidipes) Glossina pallidipes | Insects | 0.63 cycles/degree | Measured | 282.5 Hz | Measured | AndrewPMeade/FabricTools, sciphy/data_utils/datas… 2021; Lafitte et al. 2022 |
| Western honey bee Apis mellifera | Insects | 0.25 cycles/degree | Measured (not re-verified) | 220 Hz | Measured | Kelber et al. 2019; Inger et al. 2014; Lafitte et al. 2022 |
| Xenos pecki Xenos pecki | Insects | 0.1 cycles/degree | Measured | 35 Hz | Measured | Caves et al. 2018; Lafitte et al. 2022 |
| Yellowfin tuna Thunnus albacares | Fish | 16.4 cycles/degree | Measured | 80 Hz | Measured | Caves et al. 2017; Lafitte et al. 2022 |
| Zebrafish Danio rerio | Fish | 0.59 cycles/degree | Measured | 32 Hz | Measured (not re-verified) | Caves et al. 2024; Patterson et al. 2002 |