Which animal has the best eyesight?

For sheer sharpness, eagles: about 140 cycles per degree, more than twice the roughly 60 a person reaches. But "best eyesight" depends on the job — the sharpest eye is not the one that sees best at night, sees the most colours or catches the fastest movement. Here is the full ranking from our catalogue, then the other ways an eye can win.

How sharpness is measured

Visual acuity is given in cycles per degree (cpd): how many pairs of light and dark stripes an eye can still tell apart within one degree of its view. A higher number means finer detail. The familiar eye-chart score, such as 20/20, expresses the same thing relative to a typical person; this site uses the clinical convention in which 20/20 corresponds to 30 cpd, so a young adult's best acuity of about 60 cpd is 20/10. Figures for animals come from behavioural tests — training an animal to pick out a striped pattern — from the spacing of cells in the retina, or from recordings of the eye's electrical response, and different methods can disagree, so each species page gives its sources.

The sharpest eyes

The wedge-tailed eagle's figure of about 140 cpd comes from Reymond (1985), who worked from behavioural tests and from the extraordinarily dense cones in the deep central fovea, packed close to the physical limit of what an eye of that size can resolve. Raptors also have two foveae in each eye, one of which acts like a telephoto patch. Only one species in our catalogue beats human sharpness: eagle (140 cpd). Next in our catalogue come the horse at 23 cpd and the Indian peafowl at 20.6 cpd; most species sit well below us, and insects, whose compound eyes trade resolution for a panoramic view and speed, sit at the bottom.

#	Animal	Sharpness	Compared with a person
1	Eagle	140 cpd	2.3× sharper
2	Horse	23 cpd	2.6× less sharp
3	Indian peafowl	20.6 cpd	2.9× less sharp
4	Penguin	13 cpd	4.6× less sharp
5	Pigeon	12.6 cpd	4.8× less sharp
6	Dog	12 cpd	5× less sharp
7	Chameleon	12 cpd	5× less sharp
8	Elephant	10 cpd	6× less sharp
9	Duck	10 cpd	6× less sharp
10	Crocodile	8.8 cpd	6.8× less sharp
11	Goat	8 cpd	7.5× less sharp
12	Gecko	7 cpd	8.6× less sharp
13	Sheep	7 cpd	8.6× less sharp
14	Chicken	7 cpd	8.6× less sharp
15	Tiger	7 cpd	8.6× less sharp
16	Owl	7 cpd	8.6× less sharp
17	Deer	6 cpd	10× less sharp
18	Octopus	6 cpd	10× less sharp
19	Reindeer	6 cpd	10× less sharp
20	Seal	6 cpd	10× less sharp
21	Sea turtle	6 cpd	10× less sharp
22	Jumping spider	6 cpd	10× less sharp
23	Hummingbird	5.5 cpd	10.9× less sharp
24	Cat	5 cpd	12× less sharp
25	Pig	5 cpd	12× less sharp
26	Ferret	4 cpd	15× less sharp
27	Shark	4 cpd	15× less sharp
28	Squirrel	4 cpd	15× less sharp
29	Clownfish	4 cpd	15× less sharp
30	Common carp	3.6 cpd	16.7× less sharp
31	Rabbit	3 cpd	20× less sharp
32	Snake (pit viper)	3 cpd	20× less sharp
33	Bull	2.6 cpd	23.1× less sharp
34	Dolphin	2.5 cpd	24× less sharp
35	Goldfish	2 cpd	30× less sharp
36	Frog	2 cpd	30× less sharp
37	Dragonfish	2 cpd	30× less sharp
38	Bat	1.5 cpd	40× less sharp
39	Dragonfly	1.5 cpd	40× less sharp
40	Butterfly	1 cpd	60× less sharp
41	Mantis shrimp	0.8 cpd	75× less sharp
42	Zebrafish	0.57 cpd	105.3× less sharp
43	Mouse	0.5 cpd	120× less sharp
44	Housefly	0.3 cpd	200× less sharp
45	Honeybee	0.25 cpd	240× less sharp
46	Moth	0.13 cpd	461.5× less sharp

Human reference: 60 cpd (20/10). Several figures are estimates from anatomy rather than behavioural measurements, and each species page says which.

Best in other ways

At night

Night vision trades sharpness for sensitivity. Owls are among the best of any animal, with a rod-dominated retina that lets them hunt by starlight, yet at 7 cpd they are far from the sharpest. Cats, geckos, frogs and hawkmoths show other routes to the same goal, from reflective layers behind the retina to colour vision that keeps working in near-darkness.

Field of view

The widest views in our catalogue belong to the housefly (360°), dragonfly (360°) and horse (350°), against about 200° for a person. Wide-set eyes are typical of animals that must spot danger from any direction.

Speed

How fast an eye refreshes is measured as flicker fusion: the rate at which a flashing light starts to look steady. The fastest in our catalogue are the dragonfly (300 Hz), housefly (250 Hz) and honeybee (200 Hz); people sit near 60 Hz. To those eyes, a scene we see as smooth motion arrives as a quick series of separate moments.

Colour

The mantis shrimp is often called the animal with the best colour vision because it has around a dozen types of colour receptor. Thoen et al. (2014) tested that directly and found the opposite of what the receptor count suggests: mantis shrimp are poor at telling similar colours apart, and appear to recognise colours by pattern rather than by comparing receptors the way we do. Many birds, with four cone types and coloured oil droplets, are the better candidates for rich colour discrimination.

A screen cannot show sharper-than-human vision. A display can only take detail away, not add it, so a simulation of an eagle's view can show its colours and contrast but never the extra detail its eye resolves.

Sources

Carroll, Murphy, Neitz et al. (2001)
Cronin & Marshall (1989)
Doyle et al. (2014)
Futahashi et al. (2015)
Hall et al. (2003)
Hardie (1985)
Harmening & Wagner (2011)
Hart (2001)
Labhart & Nilsson (1995)
Land & Eckert (1985)
Land (1997)
Lind, Mitkus, Olsson & Kelber (2013)
Marshall & Land (1993)
Martin (1986)
Menzel & Backhaus (1991)
Peitsch et al. (1992)
Reymond (1985)
Srinivasan & Lehrer (1988)
Thoen et al. (2014)
Thoen, How, Chiou & Marshall (2014)
Timney & Keil (1992)

See it through their eyes

Animal Vision applies these same vision models to your phone camera in real time.

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