User blog comment:Arbington/The Next Cycle/@comment-2250460-20120802012255/@comment-899316-20120802020150

Not on Tuchanka, but nothing on Tuchanka is an apex predator. Life on Tuchanka is in a constant cycle of predation, where everything kills everything else. One could maybe argue that Thresher Maws are the apex predator of Tuchanka, but that's not entirely true, as krogan hunt them for food, sport, and as a rite of passage. Anyways, as the krogan have proven, on the same planet no less, a species need not be the apex predator of their planet to develop sentience and sapience. Off of Tuchanka, however, the varren quickly dominate the ecosystems of other planets, becoming apex predators, so it is entirely possible that they would develop on a world other than their actual homeworld.