primary terrain is Aquatic is presumably comfortable in a variety of watery environments.
The player chooses his ranger's primary terrain as part of the character creation procedure, subject to the DM's approval. Each ranger has only one primary terrain. Because the primary terrain reflects many years, perhaps a lifetime, of exposure to a particular environment, the primary terrain never changes. In exceptional campaign circumstances, however, the DM may allow a ranger to discard an old primary terrain and choose a new one; for instance, if a ranger whose primary terrain is Forest spends a few decades exploring the Great Glacier, his primary terrain may become Arctic. But as a rule, the primary terrain remains constant throughout a ranger's career.
In most cases, the choice of the primary terrain will be obvious, as it usually derives from the ranger's background. It will be similar to the area where the ranger was raised, or the region where he's spent most of his life. The primary terrain of a ranger who grew up in the barren wastelands of the WORLD OF GREYHAWK® Sea of Dust would probably be Desert. A ranger trained to oversee a private hunting reserve in the Wendle Wood of the DRAGONLANCE® setting would probably have Forest as his primary terrain.
A ranger's primary terrain can be randomly rolled on Table 14. The results are subject to the approval of the DM.
Once the ranger has a primary terrain, it can be used as a basis for developing the character's personal history. If the primary terrain is Arctic, for example, consider how the ranger might have become familiar with such an extreme environment. Was he hired by a king to oversee a seal refuge? Abandoned in the Great Glacier as a youth when his explorer parents were killed by a polar bear? Accepted as an apprentice by a famous white dragon hunter? Let your imagination soar!
As an option, a ranger may be allowed to specialize in his primary terrain. This confers a +2 bonus when tracking in that terrain, a +2 bonus when training animals from that terrain, general a +2 bonus on any proficiency check associated with that terrain, and