Burms can be mixed with other burms or retics, other big pythons in general. However they have a hyperactive feeding response, so imagine having to feed two at the same time.. Anyone who has actually kept a burm, retic, or the like knows just how bad it would be. Plus, they've mistaken each other for food in the past, and snapped each other's necks.. Males will fight during the breeding season.. Male and female could breed unintentionally.. If one is sick, the other gets sick too.. The list of reasons not to keep them together goes on and on.