Why does my neutered cat mount blankets and stuffed toys?
Many mistakenly think that once their cat is neutered all “sexual” behavior will stop. Not true. Although neutering removes the major testosterone stimulus by surgically extracting the testicles, the cat’s brain has already been exposed to these hormones and to a certain extent “programmed” to react in a macho fashion.
It takes a while for these hormones to leave the system, so some cats will continue to act out mating behaviors, like mounting behavior and sometimes marking/spraying, even after they’ve been neutered. Sometimes they even develop this behavior after they’ve been neutered, and may outrageously pester the other cats (or substitutes) in the household.
So, regarding substitutes, the reason your cat likes to mount blankets and stuffed toys is because these objects remind him of another cat. The blanket’s wool often has the feel (to him) of cat fur. He may also knead, purr and partake in a few “love bites” while he does it. The stuffed animal probably has even more of the same feel of a cat, because it may also have what the cat perceives to be markings—and that makes him think he’s hit the jackpot!
One note of observation: If you see the cat suckling the blanket, it could very well mean that he was taken away from his mother too quickly and is trying to re-enact kitten stage.
Another misconception people have is to think mounting is always sexual. Often, it’s a dominance display, especially when the target of the cat’s “affection” is another cat. Basically, he’s showing the other cats he’s the boss. This behavior could also be triggered when the cat becomes frustrated by other cats dominating him, or by major changes in the household. Rather than taking control back by spraying urine around the house, he uses the mating behavior.