From the introduction:
Devaronians are among the first species in the galaxy to develop interstellar travel, and the males of the species have been common sights in spaceports throughout the galaxy for thousands of years. After reaching middle age, Devaronian males are driven by an urge to wander. As such, they are often found traveling the galaxy as tramp freighter captains and scouts. Female Devaronians, on the other hand, are content to remain in a single location, and as such, raise the young and run the government of Devaron. The males send as much money as they can back to their families on Devaron, but they seldom return to the homeworld. The females are content with this arrangement, as they tend to view the restless males as disruptive to home life.