My son is fascinated by watching the wild millipedes that are plentiful outside, these guys here:
I want to set up a little tank or something so he can watch them inside, how interesting are these guys to watch? My nephew had one years ago and he seemed to think it was a waste of time.
Do they really spend 23 hours a day hiding and come out maaaybe at 4am and that is it, or are they more active and interesting to view?
My sister kept a little terrarium of them. They’re vaguely cute, although they are a little odiferous. Not really grossly stinky, but, over time, you’ll come to recognize the scent as it wafts about.
You can make up little mazes for them to run through, to see if you can train them. Decent grade-school level science project.
Why not just watch them outside? They’re not more interesting if confined.
I think your son is little, ya? For an older kid, it might be interesting to raise exotic milis - you can buy captive-bred specimens of various colours and sizes, and breeding them can be a challenge.
But just to put in a tank and watch? I wouldn’t bother.