At the carnival, especially in Cologne, there are very often women, (teen) girls and some men (Dreigestirn: Jungfrau, traditionally played by men, except the kids, Kinderdreigestirn there are real girls) wearing very long pigtails. Either dark or blonde. Not sure about boys. Some pigtails might be wigs, but most are probably real pigtails.
There are different characters. First, Tanzmariechen, then Jungfrau, Bärbelchen (blonde) and maybe some more. And of course the costumes like Pippi Longstocking.
Currently, I don’t have better pics, so I use this pic from my overalls blog (Kinderstunk und Ziegenbart 2008), Kinderstunksitzung (rating 4).
Tanzmariechen usually dancing and doing acrobatics and the pigtails often flipping or hanging upside down.
Update: This year I watched carefully to the pigtails. Most (except for the wigs) pigtails are at the back of the head instead of the sides. I wonder if they are somehow attached with pins, needles or braces or just plaited. Maybe it’s a rather modern way of plaiting. And sometimes one pigtail is at the front (shoulder) and the other on the back. Not sure if this is on purpose or by coincidence. Probably rather a coincidence, at least when dancing.