I recently tried to find out if ants can eat through tile grout like it appeared ours had but I had no luck. It just seems so unlikely and yet I really don’t know how else they could have ended coming up through there. I don’t think they just happened upon and really well rounded hole that was really close to the kitchen. I suspect it was by design but it’s really creepy to think that not even the hard tile is a barrier against these wretched invaders.