How Does Fluffy Go Potty in a Onesie? The Mystery Solved


Onesies, the one-piece pajamas with snaps at the bottom, have become popular outfits for cats in recent years. Some cat owners enjoy dressing up their feline companions, though cats are less amenable to costumes than dogs. Still, about 30% of cat owners will put their cats in seasonal outfits or costumes (source). This article explores the practical question of how cats are able to urinate and defecate while wearing a onesie given the anatomy and behaviors involved.

Anatomy of a Cat

Cats have a unique anatomy that allows them to urinate and defecate. The relevant anatomy includes the urinary tract and gastrointestinal tract.

The urinary tract consists of the kidneys, ureters, bladder, and urethra. The kidneys filter waste from the blood to produce urine. The ureters carry urine from the kidneys to the bladder, where it is stored until urination. When the bladder reaches capacity, the urine travels through the urethra and exits the body through the genital opening. In male cats, the urethra runs through the penis. In female cats, the urethra is shorter and opens just above the vagina.

The gastrointestinal tract consists of the stomach and intestines. Digestive waste accumulates in the colon at the end of the large intestine. During defecation, feces moves from the colon through the rectum and anus, exiting the body through the anal opening. The anus contains internal and external sphincter muscles that control defecation.

The positioning of the genital opening and anus allow cats access to urinate and defecate unimpeded while wearing clothes like onesies. However, onesies may interfere with a cat’s natural squatting posture during elimination.

Design of a Onesie

A cat onesie is typically designed to cover the torso and legs of a cat while leaving room for the tail to stick out. The main body of the onesie is like a small sleeveless shirt that wraps around the cat’s midsection. It usually fastens with Velcro or snaps under the belly.

The onesie extends down over the hind legs but leaves the paws exposed. There is often an opening at the rear end to allow for elimination. Some onesies feature a flap or gather elastic around this area for a snugger fit. The front legs are left uncovered for free movement.

Key design features of cat onesies include:

  • Coverage of torso and hind legs
  • Rear opening for elimination
  • Exposed front legs and paws
  • Tail sticking out the back
  • Fasteners like Velcro or snaps under belly

Onesies are commonly used after surgeries, injuries, or medical procedures that require protection and stabilization of the abdomen and hindquarters. The coverage helps prevent licking or scratching of incisions. The rear opening allows cats to freely urinate and defecate while wearing the onesie.

How Cats Urinate

Cats have a unique urinary system that enables them to urinate efficiently. Male cats have a penis with an os penis bone that assists with urine flow and proper positioning during urination. Female cats have a shorter urethra and urinate from a vulval opening below the anus [1].

When a cat needs to urinate, signals are sent from the bladder to the brain, triggering the urge to find an appropriate location to relieve itself. Most cats instinctively prefer loose, absorbent substrates like litter or soil to urinate on. As the cat squats to urinate, pressure applied to the bladder propels urine through the urethra. Cats tend to produce small amounts of highly concentrated urine frequently throughout the day [1].

If a cat is unable to urinate normally, gentle pressure can be applied to the lower abdomen to manually express the bladder. However, this should only be done as a last resort if the cat is in discomfort from a full bladder [2].

Urination in a Onesie

Cats are still able to urinate properly while wearing a onesie. Most onesies for cats have openings that allow access for urination and defecation. The onesie usually has holes cut out around the groin area or Velcro closures that can be unfastened when the cat needs to go to the bathroom (Source). The openings allow the cat to stick its genitals out and urinate normally into the litter box.

Some onesie designs also feature a flap or cutout near the tail area. This allows the cat to lift its tail into a normal urinating position. Even if the onesie covers the cat’s backside, most cats are able to hike up the material enough to urinate properly. The openings give them the access they need without limiting their natural range of motion (Source).

As long as the onesie does not completely restrict access to the genital region, cats can urinate normally while wearing the outfit. The holes and closures are specifically designed to allow cats to urinate and defecate without issue.

How Cats Defecate

Cats have a unique anatomy that allows them to defecate instinctively. Their colon is structured in a way that enables the storage and compaction of feces until it’s time for elimination. When cats feel the urge to defecate, their brain sends signals to the colon to move feces into the rectum and relax the anal sphincter muscles. This process is assisted by involuntary abdominal contractions.[1]

As feces enters the rectum, stretch receptors trigger the cat’s urge to find an appropriate location to relieve itself. Cats prefer loose, diggable substrates like litter, soil or sand to defecate in. They use their front paws to dig a hole, then back into the hole to defecate. The act of digging and burying feces appeals to their natural instincts for cleanliness and masking their scent from predators.

Normally defecation occurs easily and without issue. However, conditions like constipation or megacolon can impair this process, causing discomfort, pain and distress for cats.[2][3] Understanding the physiology behind feline defecation provides insight on potential problems and how to assist cats suffering from elimination difficulties.




Defecation in a Onesie

Cats need to be able to properly defecate, even when wearing a onesie. Most onesies are designed with access points that allow a cat to still use the litter box.

Onesies have snaps at the bottom so they can be opened for a cat to defecate. The snaps allow the onesie to be lifted up and out of the way, providing access to a cat’s hindquarters and anus so they can squat and poop in the litter box. This allows feces to pass through and fall into the litter, rather than being trapped inside the onesie.

Some onesies also have velcro closures along the back or belly area. These can be opened up so a cat can position itself over the litter box without the onesie getting in the way. As long as there is an access point that provides an opening for the cat’s bottom, it should be able to defecate properly into the litter box while wearing the onesie.

It’s important that the onesie does not constrict or block access to a cat’s anus. The openings must be large enough for them to squat and poop comfortably. As long as the onesie is designed to allow bathroom access, cats should have minimal issues defecating while wearing it. Proper onesie design helps prevent accidents or defecation outside of the litter box.

(Source: Feline Behavior Problems: House Soiling – Cornell University College of Veterinary Medicine)

Litter Box Use

Cats rely on litter boxes for urination and defecation. Litter boxes contain absorbent materials like clay, paper, or silica gel that allow cats to dig and cover their waste. Using a litter box comes naturally to most cats, as they have an instinctive desire to bury their urine and feces. This helps cats avoid attracting predators or alerting prey with their scent.

Wearing a onesie can make using a litter box more challenging for a cat. The fabric of the onesie may get in the way when a cat tries to squat in the litter box. Cats need to hike their tails and arch their backs to defecate properly, which a onesie may restrict. The onesie also prevents cats from kicking litter back to cover their waste, an important instinctive behavior.

According to some sources, cats may try to pull off the onesie when attempting to use the litter box, as the clothing interferes with their natural elimination posture and behaviors [1]. The onesie likely feels unnatural and frustrating to the cat when trying to relieve itself in the litter box.

Overall, most cats can still use a litter box while wearing a onesie, but the clothing introduces challenges. The cat cannot comfortably move or position itself as instinct drives. This can cause anxiety, resistance to the litter box, and accidents around the home.

Potential Problems

Wearing a onesie can create several potential problems for a cat when it comes to urinating and defecating.

First, the onesie may physically restrict the cat’s movements and ability to get into a proper squatting position for elimination. The fabric bunched up around the hips and rear legs can get in the way. Cats need to be able to raise their tails and hike their rears into the air to urinate and defecate comfortably. A onesie may prevent getting into this natural position 1.

Second, the presence of the onesie may cause anxiety and stress in some cats. The unfamiliar feeling of wearing clothes could disrupt normal bathroom habits. An anxious cat may begin inappropriate elimination like urinating outside the litter box 2.

Third, the onesie could accidentally get soiled if the cat can’t properly position itself over the litter box. Urine or feces getting on the onesie rather than in the box may further deter proper bathroom behaviors.

Overall, owners should closely monitor their cat’s urination and defecation habits whenever wearing a onesie, and remove it if problems arise. Consulting a veterinarian for guidance is also recommended.


Wearing a onesie does not prevent a cat from being able to urinate or defecate, thanks to the stretchy fabric and open bottom design of most onesies. Cats are capable of assuming the posture necessary to eliminate waste even while wearing these garments. The onesie may bunch up a bit around the cat’s hindquarters, but it does not restrict movement enough to prevent urination and defecation.

That said, onesies can sometimes hinder a cat’s ability to use the litter box normally. The fabric can get in the way or cause litter to cling to the garment. Cat owners who dress their cats in onesies should monitor them closely to ensure they are still able to properly urinate and defecate in the litter box without issue.

Owners should look for signs of struggle or distress in their cats while using the litter box with a onesie on. If issues arise, remove the onesie during times when the cat needs to eliminate. Only leave onesies on for short periods of time for photos and remove them if the cat appears bothered or has accidents outside of the litter box.

With proper monitoring and limited wear, cats can comfortably wear onesies on occasion without problems. Just be attentive to your cat’s needs and remove the outfit if it inhibits their ability to properly relieve themselves in the litter box.

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