Fast-moving animals 鈥� especially small ones, creatures that fly and top ocean predators 鈥� perceive time more quickly than others. That is, they can process more frames per second than slow-moving animals lower in the food chain, such as starfish, according to a comparison of more than 100 species.
鈥淲e already know that different animals perceive time differently from us,鈥� says at the University of Galway in Ireland, who presented the results at a meeting of the British Ecological Society on 20 December. But he wanted to find out, 鈥淚f you鈥檙e a predator, do you have faster eyes than if you鈥檙e an herbivore?鈥�
He and his colleagues began by reviewing previously published research on the flicker fusion test, a common measure of the rate at which animals perceive the passage of time. During the test, researchers increase the frequency of a flashing light until an animal sees it as a continuous glow, indicated by the reaction of light receptors in the animal鈥檚 retina.
Advertisement
鈥淚t鈥檚 kind of like measuring the frame rate of your eyes,鈥� says Healy. Humans, for example, can detect light flickers at speeds up to 65 flashes per second. That means they can perceive changes in their environment 65 times per second.
When they compared 138 different species, they found that the crown-of-thorns starfish (Acanthaster planci) notices changes at the slowest pace, registering just three flashes every 4 seconds 鈥� less than one per second.
鈥淚n their world, everything is just a blur,鈥� says Healy. The starfish鈥檚 temporal perception may be so slow because it is an herbivore 鈥� it doesn鈥檛 need to strike fast to get a meal. A tasty coral polyp will be in the same place even if it takes the starfish more than a second to find it. A marine predator such as a shark, on the other hand, needs to see faster to catch fish, which are constantly moving.
On average, flying animals detect light changes at a faster rate than land-bound animals, likely because they need to be able to sense changes around them quickly to avoid collisions. 鈥淚f you fly, you see faster,鈥� says Healy.
Healy鈥檚 research found that dragonflies can perceive changes in their environment the fastest, detecting 300 flashes per second 鈥� nearly five times faster than humans and 400 times faster than starfish. 鈥淚t鈥檚 almost like bullet time in The Matrix,鈥� says Healy, describing dragonflies鈥� time perception.
Sign up for Wild Wild Life, a free monthly newsletter celebrating the diversity and science of animals, plants and Earth鈥檚 other weird and wonderful inhabitants
