My second kiddo (nearly 8mo girl) will just dead eye stare at us and issue forth a guttural, rumbling growl on occasion. Usually this means that she's had a dump, easy fix, but there's so many other times she'll just let fly for no reason. She's entertained, she's warm and clean, just generally happy, but continues to do it.

It's so frustrating as we can't figure out the cause. Part of me wonders if she just likes the feeling of doing it (much like the deathlike shrieks I will do when I take myself off to the woods to vent!), but I'm intrigued to know if anyone actually has an answer to this. Last night I had it for 30 minutes straight, before she laughed for a good 5 minutes, and that was that! Nonsense!