Sea worms can distinguish moonlight from sunlight

The researchers thus determined that in the dark, L-Cgu has the form of a dimer of two identical fragments with an unstable bond between them. However, when exposed to bright light, the cryptochrome splits into two separate monomers that, even on their own, can perceive light. At high light intensities, both parts are activated, while at low light intensities only one is activated.

In this way, according to the scientists, the worms not only perceive light, but are also able to distinguish between moonlight and sunlight, and the unique protein allows them to notice how the moon phases change.