While a dog might bark to alert its neighbors, rabbits use their hind feet to alert other rabbits of danger.
That is, they thump their hind foot very hard on the ground as a warning.
This is why the rabbit in the Walt Disney movie Bambi is named "Thumper."
So why am I posting this information? Paisley the Rabbit decided at 4:45 am that there was something she needed to warn everyone about! Thump! Thump! Thump! Thump! Thump! Thump!
What was worrying her? I do not know! But obviously, it was very important to her.
Luckily, whatever it was went away and we all went back to sleep!