What is this close-up picture? (WotsThat: Frog skin)

Question

What object is shown in this zoomed-in close-up photo?

SpinelDark · Accepted Answer

Frog skin. Some poison dart frogs glow under ultraviolet light, displaying bright neon patterns that are invisible to the human eye but likely visible to other frogs—basically nature's version of a secret blacklight club membership. Scientists recently discovered this glowing ability in 2017, which means these frogs might be using UV signals to communicate with each other in ways we're only just now figuring out.

Answer: Frog skin

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