Both Drum and Bass have a habit of vomiting between 5 and 6am. They only ever puke up grass - sometimes just one blade - and a bit of fluid, but since they're mainly indoor cats the latest they're able to eat any grass is about 5pm (earlier in the winter cos they don't go out once it's dark).
What I find puzzling is that since they've last eaten any grass, they've had two meals, so how come the food has been digested but the grass is still there?
It's only once or twice every couple of weeks or so, but I'd like to know why (these are the things I think about when I've been woken at 5am and can't get back to sleep!).