Hammer sweepers

[Bayareareefer18]

Just recently noticed one of my hammers has some sweepers. Is this a feeding response or aggression? Only thing near it is other hammers

 

[Auquanut]

Following. Mine do that from time to time. No apparent rhyme or reason, and no damage to other corals.

 

[DSC reef]

It could be either, feeding response or a defense. I never paid to much attention unless a competing coral was getting to close. If it's other euphyllia nearby I would just keep an eye out but usually like species can be kept together without issue.