Is there anything you do with them that makes them really tired and sleep a little longer?

It's so strange, because for the past couple of weeks it looked like his naps where getting longer because he was having 2-3 naps a day. One time it would be 3 hours then the next would be 2 and even a third one for like an hour and a half to 2 sometimes. But it seems like he's back to his shorter naps routine. Does this mean anything? Now i'm lucky if he'll go for an hour.