How Do Our Eyes Rate Against the Animal Kingdom?
23 June 2016
There are a lot of things that humans have excelled at, including communication and advanced tools that have allowed us to build civilisations. Humans don’t always beat the animal kingdom when it comes to physical attributes however – we are easily outstripped when it comes to vision in the wild.
Fast Perception Time
A recent study measured the visual perception speed of various animals, with surprising results! By blinking a light on and off at different frequencies and monitoring brain activity, researchers could tell how fast the subject could register light flashes.
Humans clocked in at 60hz, meaning our brains can perceive about 60 light flashes per second. The common housefly, however, blew away all other participants, able to perceive 250 flashes per second! That would be like seeing everything in slow-motion—and it explains why flies are so hard to swat!
Superior Night Vision
Our feline friends have the upper hand when it comes to navigating at night. Cats, who are naturally nocturnal animals, have several advantages that make their eyes better in dim conditions:
- They have a higher concentration of light-detecting “rod” cells, as opposed to our colour-distinguishing “cone” cells.
- They have an additional reflective surface behind their retinas called the tapetum, which reflects light into photoreceptors (and explains why their eyes glow in photos).
- Their slit-like pupils can expand or contract farther and faster than ours to adjust to lighting.
It’s estimated that cats only need one sixth the light we do to operate at night!
Incredible Colour Range
The three types of ‘cone’ cells in our eyes are sensitive to red, green, and blue light, but that range makes up only a small part of the light spectrum.
Other animals have more types of photoreceptors sensitive to light that is invisible to us! For example, birds have four types, allowing them to see ultraviolet light, butterflies have five, and the bizarre mantis shrimp has up to sixteen! Scientists are still researching what possible use this amazing visual range is to the crustacean, but they may use it as a communication tool.