Magnaraks grow relatively fast for their size, but when they're born they are not ready to face the dangers of the Forest and surely aren't ready to be ridden, so handlers will have to train them to ensure they'll become loyal healthy Magnaraks.
Acts and Training are based on the 8 fundaments of the Citadel, that like legs keep it strong above the dangers of the Forest.
Unity (because we are one with our Mother Arakne and her children), Loyalty (because we must sustain one another), Courage (because our hearts are strong), Trust (because we must shield each other's weaknesses), Knowledge (because knowing our land is a duty and a honor), Good