The ancestors of modern sleestak were the altrusians. Their civilization fell approximately 1,000 years earlier. The sleestak sometimes use the term "altrusian" to refer to themselves and sometimes to refer only to the true altrusians. Physically, the altrusians were similar to sleestak, with the former marked by a shorter stature, an extra finger on each hand, and a golden yellow skin tone. Intellectually they were very different, however. The altrusians possessed advanced psionic technologies based on light crystals and understood a great deal about the operation of the Land of the Lost. They strove for calm emotionlessness and as a result could be both cooperative and quite callous. Altrusians have a very strict code of honor: they cannot allow others to show more self-control or make greater personal sacrifices than themselves. Occasionally, a sleestak will be hatched that is a "throwback" to their altrusian ancestors, being born with greater intelligence and with an innate knowledge of altrusian history and technology—though not, for some reason, knowledge of the pylons or matrix operation. The other sleestak regard these throwbacks as a threat, and so they are also sacrificed to the sleestak god when detected. Instinct: Investigate ancient technology