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How does a dog see the world?

By: Russell McLendon on Aug. 6, 2013, 9:42 a.m.
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Squirrels

Despite their color and acuity issues, dogs are uncanny motion detectors. A stationary squirrel may blend into the background, but any sudden moves could alert dogs as far as half a mile away.

Canine retinas are packed with light-sensitive "rod" cells, helping them detect slight motion in daylight or darkness. A 1936 study on police dogs found some could identify moving objects from 2,900 feet away, but their range fell to 1,900 feet when the same objects were motionless.