system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do human eyes turn red when a flash is used but dog eyes turn green?

Edit: Explained, everyone! Thank you for all the great answers! Very much appreciated!
gpt
We have slightly different retinas than dogs do. Dogs have the ability to see in very low lighting because what appears green is a layer in their eyes that reflects light within the eyeball in order to increase the amount of light that hits the photoreceptors. Humans lack this adaptation but many other vertebrates have it. The red is most likely just a reflection of blood vessels.