Rat kangaroos have a commensal relationship with the dung beetle Onthophagus. This beetle lives on and around their tail region. The males bring dung to the females and they lay their eggs beneath the dung balls. The beetles get a benefit as they use the dung for food. This is an example of commensalism. There is mutualism between kangaroos and bacteria in their gut. Both organisms benefit from this relationship. Kangaroos feed on plant fibers and the bacteria carry out fermentation. They are provided with a place to live and food and help to break down the kangaroo's food, as well as produce vitamins for the kangaroo. They also convert nitrogen containing compounds into proteins for the kangaroo to use.