strange cat behavior

Question
Hello, my two cats are lovely, but have pretty strange habits. Charlie is 10 years old and his little brother Bob is about 6.  I am pretty sure that the strange behavior Bob exhibits is learned from Charlie.
When I first had Charlie as a kitten he had an older brother named Big Love.  Big Love was a very normal cat, and a bit shy.  Big Love basically taught Charlie to use the little box, play, etc.  But Charlie did not use the litter box the same way that big Love did.  Charlie would eliminate, not cover it, and then scrape the sides of the litter box dome almost making himself believe that he was burying it.  He has always done that, and when we got Bob as a kitten, Charlie basically taught Bob to use the litter box the same way.  Needless to say it is a very stinky situation when the feces are not being buried, especially living in a one bedroom apartment.
We tried a Cat Genie, which worked really well for a while, but my cats are very large (bob=21 lbs, charlie=19 lbs) and they didnt fit in the bowl of the genie very well so their urine would leak out the sides and it was just too unsanitary and annoying to deal with so we got rid of that.
My questions are: Have you ever heard of other cats doing this?  I never have from anyone I have ever asked, including their vet.  And also, is there any way to train them to bury their stuff?  It may be too late to train them, or maybe not even be possible, we would just like some relief from the stench and noise.  Charlie also after scraping the dome will come out of the litter box to the carpet and start picking and scratching at the carpet, and sometimes Bob would scratch the dome, come out of the litter box and scrape the cabinet to make the paint some off.  Strange boys of mine!  Any input would be greatly appreciated, thanks!

Answer
Alexandra,

First, the not covering the poop behavior that some cats show that is a throwback to their ancestors in the wild. The dominant cat of the group did not cover the feces as a show of his dominance. Only the secondary cats covered it. In a domestic cat normally you are the dominant one and your cat is secondary so he covers his feces...but Charlie may think HE is the dominant one!

Bob probably learned from watching Charlie. That is how the term "copy-cat" came about.

But most common reason for not burying the feces is because it is a message to you that something is not right with his litterbox. You might try changing brands (or types) of litter to see if that affects his behavior. I would suggest getting a bigger litterbox (like the under the bed storage containers that have low sides), and making the litter deeper. As a cat grows he can feel too confined in his present box and feels he doesn't have enough room to properly cover his feces without getting his paws 'dirty'. You can also try some children's play sand one time instead of litter and see how he behaves. You can get it at Home Depot or similar building supply store.

Tabbi