A Veterinarian’s Perspective

As a licensed veterinarian practicing in Texas for over a decade, I’ve learned that “unusual cat behavior” means very different things to different people. For one client, it’s a cat that suddenly starts hiding under the bed.

For another, it’s a normally quiet cat howling at 3 a.m. For me, unusual behavior is often the first and sometimes only clue that something medical is going on.

Cats are subtle. They don’t limp dramatically or cry out the way dogs often do. They change habits. And if you know what to look for, those shifts tell a story.

Hiding, Avoiding, and “Being Antisocial”

One of the most common concerns I hear is, “She’s just not herself.” Usually, that means a previously social cat has started hiding, avoiding interaction, or retreating to unusual spots like closets or laundry baskets.

In my experience, hiding is one of the earliest signs of pain or illness.

Last spring, a client brought in her middle-aged indoor cat, who had started spending most of her time behind the washing machine. The owner assumed the cat was “just stressed” because of visiting relatives. But during the exam, I found abdominal discomfort. Bloodwork and imaging later confirmed pancreatitis. The hiding wasn’t moodiness. It was pain.

I’ve found that owners often wait too long in these cases, hoping the cat will “snap out of it.” If your cat suddenly withdraws for more than a day or two—especially if appetite or grooming changes as well—I recommend a veterinary visit rather than watchful waiting.

Sudden Aggression in a Previously Gentle Cat

Few things unsettle owners more than a cat who suddenly swats, bites, or growls.

Aggression that appears out of nowhere is rarely a personality issue. It’s frequently a pain response. Dental disease, arthritis, urinary tract inflammation—these are common culprits.

I remember a senior cat who began attacking his owner’s legs when she walked past. She was convinced he’d become territorial. On the exam, I noticed he flinched when I touched his lower back. X-rays showed significant arthritis in his spine and hips. Every time she brushed past him, even lightly, it likely hurt. Once we started pain management, the “aggression” resolved within weeks.

In my professional opinion, punishing a cat for sudden aggression is one of the biggest mistakes owners make. If behavior changes abruptly, assume discomfort until proven otherwise.

Excessive Vocalization at Night

Nighttime yowling is another frequent complaint. In younger cats, it may relate to boredom or reproductive behavior if they aren’t spayed or neutered. But in older cats, I immediately consider medical causes.

Hyperthyroidism is common in senior cats and often presents with increased vocalization, restlessness, and weight loss despite a good appetite. Cognitive dysfunction—similar to dementia in humans—can also lead to disorientation and nighttime crying.

A few years ago, I saw a 15-year-old cat whose owner hadn’t slept properly in months because of the howling. She thought her cat was “just getting clingy.” Bloodwork revealed hyperthyroidism. Once we started treatment, the nighttime noise decreased significantly.

What stands out to me is how often owners interpret vocal changes emotionally rather than medically. Cats don’t usually “complain” without a reason.

Litter Box Changes: The Red Flag I Take Seriously

If there’s one behavior I urge clients never to ignore, it’s a change in litter box habits.

Urinating outside the box is frequently labeled as spiteful or behavioral. In my clinical experience, it’s far more often medical. Urinary tract infections, bladder inflammation, crystals, and even early kidney disease can all cause accidents.

I recall a case involving a young male cat who began urinating on the owner’s bed. She was furious and had started confining him to a small bathroom. When we examined him, he showed clear signs of urinary discomfort. A urinalysis revealed inflammation and crystals. Left untreated, that situation could have escalated to a life-threatening blockage.

Once we treated the underlying issue and adjusted his diet, the inappropriate urination stopped.

Cats associate the litter box with pain if they experience discomfort while using it. So they try a new location. That’s not defiance. It’s avoidance learning.

Overgrooming and Bald Spots

Excessive grooming that leads to thinning fur or bald patches is another behavior owners often misunderstand.

Stress can absolutely play a role. But I’ve diagnosed allergies, flea infestations in meticulously clean homes, and even neuropathic pain presenting as overgrooming.

One indoor-only cat I treated developed symmetrical hair loss on her belly. The owner insisted there were no fleas—and she was probably right about not seeing any. But it only takes one bite to trigger a reaction in a sensitive cat. After starting proper flea prevention and addressing environmental allergies, the grooming decreased.

In other cases, I’ve seen overgrooming tied to stress from subtle changes: a new pet, rearranged furniture, or even construction noise next door. Cats are creatures of routine. Disruption matters more to them than most people realize.

Repetitive or “Odd” Behaviors

Occasionally, owners describe behaviors that sound almost compulsive: tail chasing, staring at walls, and sudden, frantic running.

Some of this is normal feline behavior, especially in young cats. But repetitive, escalating patterns can indicate neurological issues or anxiety disorders.

I once evaluated a cat who would suddenly dash through the house as if startled, then lick her tail intensely. After ruling out skin disease and pain, we considered feline hyperesthesia syndrome. Management required environmental adjustments and medication. It wasn’t common—but it was real.

The key lesson? If a behavior appears extreme, repetitive, or worsening over time, it deserves attention.

Common Mistakes I See Owners Make

Over the years, I’ve noticed patterns in how unusual behavior gets handled at home:

Assuming it’s “just stress” without checking for medical causes

Trying punishment or confinement

Changing food repeatedly without guidance

Waiting weeks to see if things improve

I understand the instinct to hope a problem resolves on its own. Veterinary visits cost money. Life gets busy. But cats compensate quietly. By the time symptoms are obvious, the underlying issue may have progressed.

In my own practice, I’d rather examine a cat and find nothing serious than see one after weeks of silent suffering.

When to Act

If your cat shows any of the following alongside unusual behavior—reduced appetite, weight loss, vomiting, diarrhea, changes in thirst, or changes in litter box habits—I recommend scheduling an exam promptly.

Even subtle behavioral shifts that persist more than a few days deserve a closer look.

Cats rarely change habits without a reason. The challenge is that the reason isn’t always obvious on the surface.

After years in practice, I’ve learned to respect those small signals. The cat hiding in the closet, the sudden growl, the missed litter box—these are conversations. Our job is to listen closely enough to understand what they’re trying to say.