S.R.
the first real laugh, that made all of us laugh til' tears poured was around 3 and a half months. But that developed dramatically to a 5 month old belly laugher. The best thing so far I have ever experienced! Now 7 months old, he has a whole "laugh vocabulary" that he pulls out for each favorite thing..
Gramma's puppy gets a shreiky laugh..
While daddy's goofy antics get a screaming laugh.
The best is his brother making loud fart noises for his entertainment, he thinks this is the best and lughs like a maniac. Guess they know something we don't eh?