Oh, I did not know that! Thanks!

The House Rabbit Society has fun facts:

Rabbits are very social creatures that always choose to live in groups when given the chance. A warren is the name given to the place where a fluffle lives. Some people also call a group of rabbits a colony.

Like cats, happy rabbits purr when content and relaxed. The sound is comes from teeth chattering softly.

Source: https://rabbit.org/2022/03/basic-rabbit-facts/