With most species of snakes there is no territoriality. There are exceptions, in certain subspecies of carpet pythons, Morelia spilota sp., males will actually engage in combat for breeding rights. This may happen with other species too. There are other potential problems. Some species of snakes, such as indigos, Drymarchon corais couperi, black headed pythons, Aspidites melanocephalus, most species of kingsnakes, Lampropeltis ssp., and many others, are naturally ophiophagic, so there can be a danger with them eating smaller cage mates, (and sometimes not as much smaller as you may think.) I personally avoid housing snakes together long term for a number of reasons, mostly that it is harder to monitor their health and overall condition.
