What do you mean?
What I mean is that this poster has got to be a joke. Distinct skeletal structure? All vertebrates have that.
Straight OR curly tail? All pigs with tails are now invasive.
Erect OR floppy ears? All pigs with ears are illegal.
Any characteristics not currently known to the DNR? Get real.
Some 8th grader in Iowa made this poster, and he's got y'all all worked up about it. The icing on the cake for me is the apostrophe in juveniles. Get real. It's either that, or the Michigan DNR is comprised of serious, serious morons. I'm an optimist, so I'll cast my lot with the former.