DEAR JOAN >> We recently got a new kitten. Mind you, this is our third cat in 30 years. Our first one lived with us for nearly 16 years before passing away. The second one lived with us for over 13 years and just recently passed away. Both our cats were females, but this new kitten is a male.

He is about 9 weeks old and has been with us for the past two and a half weeks. Although he has been using his litter box regularly from day one, for the last two days, he has started peeing in our bed.

For the first week and a half, he could not climb onto our bed. He learned how to do it, and now climbs and plays on the bed. He will sleep on the bed during the day, but at night, he sleeps under the bed, although he has a bed of his own.

How do we discourage him from peeing in our bed? I washed the bedding, and still no luck. He pees sometime in the early morning, or at least that’s my guess.

— Kalpana Thatte, San Jose

DEAR KALPANA >> The first thing to do is to take the kitten to the vet. That’s always a good idea whenever a pet starts doing something out of the norm. The vet will check for a bladder or urinary tract infection, which is a common cause for cats peeing outside the litter box.

If the kitten gets a clean bill of health, it will be time to look at the other reasons that could be causing litter box avoidance, although it might fall into the realm of “cats being cats.”

Stress is a common cause, but finding out what has stressed your cat isn’t easy. Simple things, such as a change in the household can cause stress to a cat. He might be having trouble adjusting to his new home.

Has your kitten been neutered? Cats, especially male cats — and more especially unneutered male cats — use urine to mark their territory. Your kitten, having conquered the climb up Bed Mountain, might be planting his flag there, so to speak. Neutering often eliminates that problem.

Cats can be obsessive about their litter boxes — obsessions that can change with the shifting sand. One day the litter is just perfect; the next, the cat hates it with a passion.

Trying to figure out what’s got your kitten’s nose out of joint regarding the litter box might not be worth the struggle, except for making sure he is healthy. Instead, here are some ways to discourage the activity.

Washing the bedding is good, but you probably need to also clean the mattress with a product designed to remove the smell of pet urine. Check at your favorite pet supply store.

Start playing with the cat on the bed and feeding him treats there. He will begin to associate the bed with food, making it less likely he’ll pee there.

Use a fine grained, unscented, clumping litter and don’t use plastic litterbox liners, which can annoy cats. You might also want to add a second box for variety.

Until he gets the message, spread a plastic shower curtain on the bed when not in use. Cats typically don’t like the feel of the plastic or how the pee puddles on it. If he’s doing it while you’re in the bed, you might need to banish him from the room at night.

Lastly, be patient. He’ll eventually get it.

Contact Joan Morris at jmorris@bayareanewsgroup.com.