Danny was adopted from the local bunny rescue, after bonding with Reggie during a bunny meet and greet stay at the sanctuary. Most bunnies do better in pairs, but they both have to be spayed or neutered and have to be introduced to their partners slowly. They also have to spend time with them to ensure that they are a good fit. Danny was taken with Reggie right away and so she didn't get to meet any other bunnies.
Danny is more outgoing than Reggie and he helps convince her that life is fun and that exploring is ok. Usually, when you see one bunny, the other one isn't far behind.