Dolphin culture depends heavily on the variants. Overall, their in-race culture involves a hierarchical harem system of the four variants. Exceptions can be found, but Dolphins who grow up around non-Dolphins will still tend to attempt to form harems, either with themselves as leader or as another individual they perceive as stronger as leader. Typically they welcome non-Dolphins into their harems as well, but not always. Harems are not strictly sexual, but they often are when it comes to Dolphins.
At the bottom of the system are the Plantas Dolphins - the smallest, at around 4'-6'. Plantas are often characterized as ditzy dreamers who have no real passion or guidance and need the instruction of those higher up in the hierarchy, but many would disagree with this stereotype. They are the most common Dolphin type, and the kind most others will think when a "Dolphin" is mentioned.
Next on the ladder is the Delphin, the second-most common variant, at 5'-7'. Delphin are said to be hardworking and eager to please, but often become antsy without something to do and fidget with their hands if they aren't holding something. Their markings are a surefire way to identify them, and many will use body paint to accent these markings in a way to appear more attractive. When a harem lacks a Pseudorca or an Orca, Delphins will often squabble among themselves for who gets to be leader.
Second-highest are the Pseudorca, which mimic the coloring of Orcas but lack the paler markings, and stand at 8'-12'. Pseudorcas are stereotyped as calm, calculating, and shifty, and most would probably agree with this. They are reasonably rare and while they don't lord this fact over the other Dolphins' heads, they tend to carry an atmosphere of that they know best. Pseudorcas, when not around Orcas, often take control of a harem, and many seek to keep that control. While most would give up their harem to an Orca, if one so happened to appear, there are a few that would battle to keep it. Most of the time, giving it up is preferred, as they will likely become the Orca's right-hand Dolphin.
Finally, at the top are the Orca, the rarest and tallest, at 9'-11'. Orcas are almost unanimously in charge of harems, and this has led to most assuming they are arrogant, mocking, and egotistical. Many would angrily deny this, and claim instead they're fair and kind leaders who take care of their underlings. Most non-Dolphins would only know of Orcas if one was in control of a harem nearby; otherwise they may not even know what one is unless they took race informational classes. They tend to be surrounded by a small group of Pseudorca which are their trusted confidants, and then manage the rest of the harem through these individuals.