What is up with the grunting?

blackphoenix

I've seen posts on here about, "Aww, my 5 week old grunts now", or, "My 8 week old just started grunting."  Ok, I get it. . .babies start grunting and cooing around that time.  But here's a question.  Why is my 5 month old doing it?  It's been the last week or two that he just grunts.  He used to make other noises, cute baby noises, but now he just grunts.  He seems relatively happy.  He eats just fine, sleeps normal (well, what's normal for him), and has been pooping fine.  Is this just a phase that babies go through? 

GRKaters

Mine seems to do it when he is bored or wants a change of scenery. Moving him to a different spot (saucer, bouncer, mat, etc.) or carrying him around and talking about things (the mirror, the Christmas tree, etc.) seems to settle him for a while.