Prior to the 2260s decade, the Scalosians became infertile after suffering radiation sickness. As a result of this, Scalosian bio-chemistry was accelerated to the point where they experienced hours as other lifeforms experienced minutes.
In the year 2268, the Scalosians hijacked the Federation starship USS Enterprise in an attempt to use the male crewmembers to repopulate their species. Fortunately, Captain James T. Kirk was able to stop the Scalosians from succeeding, and returned them to Scalos. (TOS episode: "Wink of an Eye")