It’s really hard to hit a fly with a fly swatter because they’re basically seeing everything in SLOW MOTION.

Humans and other animals don’t really see things as one continuous video.  Our brains are constantly piecing together images so everything LOOKS like it’s continuous.

How fast it happens is called “flicker fusion rate.”  For humans, it’s about 60 times a second.  Kind of like a video camera that shoots 60 frames per second.  But not all animals have the same flicker fusion rate.

For turtles, it only happens about 15 times a second.  So things look like they’re moving a lot faster for them than for us.

For houseflies, it’s around 250 times a second.  Which means they’re seeing the world move four times SLOWER than us.  So if they see a fly swatter coming their way, they can move before it hits them.

We’re just smarter than flies, so sometimes we catch them by surprise.