When I trained mine to come when I whistle, I would pick them up and whistle at them as I handed them a treat, when I used something like ferretvite, which they consider a treat, i would whistle the whole time they were licking away at it. This seemed to wrok very quickly I had them coming to my wistle in about 2 days. Yes I am a proud papa. They sometimes need me to whistle a few times, If they have to come a long distance they get distracted, darn ferret attention span, but they always come. You may also consider the possibility that Loki may be deaf. I don't know if you have ruled this out already but if he knows treats are available when you snap your fingers, it should t least get his attention briefly. [Posted in FML issue 2373]