How they see
How does a crocodile see the world?
A sharp streak across the waterline
A crocodile lurking at the waterline comes equipped with the perfect eyes for the job. A horizontal streak of sharp vision runs across its retina, giving it a clear, panoramic band exactly along the water's surface where prey comes to drink. A vertical slit pupil and a bright reflective layer then turn those same eyes into formidable night-hunting tools.
See through their eyes
Human ≈ 60 cpd (20/10)
How sharp is a crocodile's vision?
Its eyes resolve about 8.8 cycles per degree (20/70), while a human reaches around 60 cpd (20/10). Its field of view spans about 270°.
How does a crocodile see a human?
Its eyes resolve about 8.8 cycles per degree against your 60, so a face has to be roughly 7 times closer for it to pick out the detail you do. Your outline and your movement read clearly; your expression does not.
Colour comparison
How each colour shifts when seen through this animal's eyes, using the same colour model as the app. Tones a screen can't emit (such as ultraviolet) are shown as an approximation.
What colours can a crocodile see?
Limited three-cone colour, weak in the red; sharp across the horizon, blurrier above and below.
Photoreceptors
Three cone pigments (limited colour) + a horizontal "streak" fovea + tapetum lucidum
Cone peak sensitivities
- S (blue)443 nm
- M (green)535 nm
- L (red)566 nm
How does a crocodile see in the dark?
Excellent; vertical slit pupil and tapetum for night hunting.
How does a crocodile's vision compare to a human's?
A crocodile sees around 20/70 to your 20/20, and although it carries three cone pigments like you, its colour vision is thought to be more limited than yours. For scanning the horizon its horizontal streak of sharp vision beats your eye, and its night vision far outstrips yours.
What is special about a crocodile's vision?
- Horizontal streak of high acuity
- Vertical slit pupil
- Tapetum eyeshine
What the research shows
Two studies on two different crocodilians underpin this page. Sillman, Ronan & Loew (1991) combined histology with microspectrophotometry in the American alligator, Alligator mississippiensis, finding single cones near 443 and 535 nm, double cones whose principal member peaks near 566 nm and accessory member near 503 nm, and rods at 503 nm. Rods dominate that retina, and coloured oil droplets are present. Nagloo, Collin, Hemmi & Hart (2016) studied the saltwater crocodile, Crocodylus porosus, and found single cones near 424, 502 and 546 nm, together with a peak spatial resolving power of 8.8 cpd carried by a horizontal foveal streak.
Both animals have three cone pigments, the receptor basis for trichromatic colour vision. The peaks on the chart, 443, 535 and 566 nm, are the alligator's; the saltwater crocodile's own values sit somewhat shorter, so the chart is a close relative's set rather than a portrait of one animal. The acuity figure, 8.8 cpd or roughly 20/70, is the crocodile's own and applies along the streak, with detail lower above and below the horizon line. The same eye pairs a vertical slit pupil with a reflective tapetum, which together span a very wide range of light levels. A screen can lift shadows and protect highlights, but it cannot recreate the sensitivity that combination gives the animal in dim water or at night.
Guides: Which animal has the best eyesight? · All guides
Scientific sources
- Nagloo, Collin, Hemmi & Hart (2016)
- Land & Nilsson (2012)
- Sillman, Ronan & Loew (1991)
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