Pistol shrimp question

[Fishyj]

Hi all, tried finding an answer but I couldn’t. Why does my pistol shrimp every night close its burrow up and then some time the next day it will reopen it. He has 1 main opening and I say about 6 other ones he will occasionally open. This is the first one I have ever had and find him really interesting. The one good thing about having him is I don’t think I will ever have to stir up the gravel because it is constantly being moved and this thing just excavates all day long.

 

[DrkNMighty]

I would assume it’s a step they take to hide from predators overnight.