Crazy cat sucking is not crazy at all. It is totally predicable and normal…if you are a domestic cat kept in a permanent state of kittenhood by your human caretaker.
Whether we know it or not, nearly all of us through caring for our cat, condition him or her to be a permanent kitten.
This is because we feed, groom and generally look after our cats (if we are doing a good job) which is the kind of thing a mother cat does with her kittens before they become independent and leave home.
In the wild, at a certain stage in a young cat’s development he or she will leave home (the natal area) and find his own home range, a place he can call his home.
In the domestic situation the cat never leaves home and therefore undergoes a state of permanent suspended development.
As a consequence you will, on occasion, see domestic cats sucking on jumpers, ears, you name it. The cat believes that he is suckling on mother’s breast. At the same time the cat might knead around the area where he believes he is being nursed by mother to encourage milk flow (obviously there is no milk but the behavior is instinctive).
Here is an example:
And here is another similar example:
It is meant to happen more commonly if the cat has been weaned too early. This can also lead to pica – chewing on anything that comes to hand and eating it.
This behavior begs the question as to whether we should do something to allow our cat to grow up. I am not sure what we can do but it is a thought nonetheless.