Rabbits in severe distress make a loud noise such as a scream or a howl. It means the rabbit is in great pain or is very frightened. The noise is described as sounding similar to a screaming child.
Rabbits in general are fairly quiet, but they do make noises. They growl when threatened or annoyed. They make honking noises and sometimes purr like a cat. Rabbits also create noises by thumping the ground with their hind legs. This thumping is thought to be either an expression of displeasure, or a warning signal to other rabbits that something scary has been sighted.