All three of the hyenas have been neutered, and all are believed to be siblings (they were wild-caught in Kenya, and were part of the University of California (Berkeley)'s research colony until 1991).
This images shows Tigger (m) on the left, and I believe Rabbit (f) on the right (they were named after Winnie the Pooh characters). There is a heated pad in the cave in the background to help keep them comfortable.