Bear in mind that all the animal folk are artificial beings engineered by the big bad of the first half, and that is the main reason why they can’t tap into spiral energy. I believe at one point it’s stated that they can’t reproduce. Viral is the only one the eventually gets access to some spiral power, but he was given the special gift of immortality and also spent a shit ton of time with the humans and trying to better himself. There is a small undercurrent theme, mostly shown through Rossieu (fuck if I know the spelling) regarding the danger of spiral power, that is, unrestrained uncontrolled evolution growth expansion and reproduction against the limited resources of reality. This is also part of why the end hits so damn hard, as it basically says “Fuck resource scarcity, we’ll find a way. We’ll fucking find a way to rewrite reality if we need to, but we’re never going to stop trying to keep growing and moving forward”