Q: Why does my ferret have no “normal” ferret interests?
A: To fully answer this I guess I would have to decide how “normal” ferret behavior is defined. Ferrets are a lot like people, and their interests differ. Ferrets interests also change as they age. Often ferrets will get into a rut, just like people do; ferret owners can spend time with them encouraging new activities by introducing new smells, new foods, play time with us or other ferrets, etc.
Note that as a ferret ages or if it feels ill, it will be less active.