Salsenes evolved from the Sals. At the time, many of Ishtars species were dying out due to the Vastan Mass Extinction. Sals evolved sapience in order to survive the event. As a dumb amphibian, Sals did not stand much chance of surviving. However, an increase in thought capacity allowed them to explore new areas, and to try new foods. And as life became more and more difficult, only the most intelligent Sals were able to survive and reproduce. Eventually, they became fully sapient in their own right.