Suckling kitten

OK, I'm just curious if anyone else has ever seen this. I know that kittens who are taken away from mom too soon tend to retain their suckling behavior. We've got a kitten at our shelter right now who was about 5 - 6 weeks old when she came in. Her belly was always wet & I could never figure out why. Well last weekend I found out. She sits on her bum & suckles her own nipples.?? I've never seen this before, is this little lady just strange or has anone else seen this?

We had a kitten come in who did that to herself and there was no breaking her of the habit. She had other issues, as well. She was not properly socialized. Honestly I'm not sure what happened to her - I am pretty sure she got a home.

Other forum members who have more cat behavior insight might be able to answer the WHY question.