Unlike most races in the galaxy, Tholians are a non-humanoid race. They are presumed to be silicon-based, although no outsider has ever conducted a documented medical examination of a Tholian. Tholians require a primarily methane atmosphere kept at a temperature of several hundred degrees. Thus, the Tholians may never be capable of "face to face" negotiations with other cultures. Instead, they typically allow carefully chosen representatives to speak for them over long distance communications.

The Tholians are a startlingly advanced technological race, and place a high reliance upon scientific precision and accuracy. Even before Federation contact, legends in that region of space emphasized Tholian punctuality. This characteristic corresponds with other Tholian traits, such as their innate understanding of the complexities of quantum and temporal mechanics. Tholians always seem to be in the right place at the right time.

Tholians in general have a curious disregard for humanoids' straightforward, two-dimensional thinking. Their military tactics are particularly baffling, taking advantage of multidimensional space that does not fully correspond with current theories of physics; furthermore, the Tholians' extensive technological proficiency gives them a significant edge. Likewise, some Tholian annexes seem completely unnecessary to Tholian defense, while other sectors that would seem to hold great strategic value for the Tholians remain unclaimed.

Anyone required to communicate further with the Tholians should consider the following: be precise in stating your intentions, do not vary from what you profess, respect the Tholian need for anonymity and pseudonymity, and expect the unexpected.