Depends on the male. I hate to portray all intact males as aggressive because that simply isn't true. But having said that, unless you are using them for breeding, there really is no reason to keep them. Hormones do play a role and they can get aggressive. If there are no females around, then they probably won't get aggressive. If you want them for a guard llama, then that is not a good situation. They will breed the animal that they are protecting. Depending on size, they could kill the animal with getting on top of them and breeding them.