Why Do Cats Use Litter Boxes And Not Go Outside?


Cats are known for their fastidious grooming habits and their instinctive desire to bury their waste. Unlike dogs, cats almost always use a litter box inside the home rather than going outside to relieve themselves. This behavior stems from cats’ natural tendencies and ancestry as solitary hunters. In this article, we will explore why cats use litter boxes instead of going outside. The key factors include domestication, territoriality, instinct, sense of smell, cleanliness, training, convenience, and health considerations.


Cats originally descended from desert-dwelling wildcats that inhabited areas in North Africa and the Middle East. According to The Evolution of House Cats, archeological evidence indicates the earliest domestication of wildcats occurred approximately 10,000 years ago in the Near East. Genetic analysis suggests that cats were first domesticated in the Fertile Crescent region around modern day Israel, Jordan, Syria, Turkey and Iraq.

It’s believed that wildcats initially moved close to human civilization to take advantage of rodents attracted to grain stores in early agricultural settlements. Over time, humans began taming and breeding the cats. Cats were prized by ancient Egyptians and became widespread throughout Europe by the 4th century AD according to The Natural History of Domestic Cats. Selective breeding of cats over thousands of years has produced the wide variety of domestic cat breeds we know today.


Cats are inherently territorial animals. In the wild, cats will establish a territory that they mark and defend from other cats. This territorial behavior continues even when cats are domesticated and live indoors (source).

An indoor cat considers the entire house as their territory. They want to feel like they have ownership over their space and can retreat to a safe zone when needed. Using a litter box allows a cat to establish control over at least a small part of their indoor territory (source).

Territorial marking is also why some cats may spray urine around the house. It’s a way for them to claim an area. Providing a litter box gives them a designated spot to mark as their own.


One of the main reasons cats use litter boxes is due to instinct. According to an article on WikiHow, cats have an instinct to bury their waste in order to hide their scent from potential predators. In the wild, the smell of a cat’s waste can allow other animals to track them down. Burying their poop helps conceal their location. This instinctive behavior to bury their waste has simply translated over to cats using litter boxes indoors.

Cats have a natural desire to keep their living space clean by eliminating waste far away from where they sleep and eat. According to Livescience, cats meticulously bury their poop due to their history of using urine and feces to mark territory. By burying their waste, they help avoid alerting predators to their core habitat.


Cats have an extremely powerful sense of smell compared to humans. Cats have about 200 million odor receptors in their noses while humans only have around 5 million (Cat Senses). This means cats can smell about 14 times better than humans can (How do a cat’s five senses compare to ours?).

Cats rely heavily on their sense of smell to gather information about their environment. They have a vomeronasal organ that detects pheromones, which allows them to perceive things undetectable to humans. A major reason cats use litter boxes indoors is to eliminate smells. Cats are very clean animals and don’t like the smell of their waste. Burying their waste in litter helps contain and mask odors.


Cats are meticulously clean animals that spend a large portion of their day grooming themselves.[1] They have rough tongues that can remove dirt and distribute oils across their fur and skin. Their saliva also acts as an antiseptic, helping keep their mouths clean.[2] This fastidious grooming helps control shedding and keeps their coats healthy and free of debris. It’s an important part of a cat’s daily routine.

Cats are sensitive to smells and dislike areas that are unclean or soiled. This helps motivate their use of litter boxes, as they innately prefer to eliminate in clean, dry areas. It’s an instinct that dates back to their days as wild desert dwellers, where they would hide their waste to avoid attracting predators or contaminating limited water sources.[3] This preference for cleanliness and avoidance of foul odors helps facilitate litter box training.

[1] https://www.petfinder.com/cats-and-kittens/health-wellness/grooming/are-cats-clean/
[2] https://ask.metafilter.com/106961/Not-buying-this-cats-are-clean-nonsense
[3] https://pethelpful.com/pet-ownership/are-cats-cleaner-than-dogs


Litter boxes provide a designated location for cats to be trained to eliminate indoors. Kittens begin to learn to use the litter box at around 3-4 weeks old. Their mother teaches them by example, showing them where to go. It’s important when litter training kittens to place them in the litter box after meals, naps, and playtime so they associate the box with eliminating. Use positive reinforcement like treats and praise when they use the box successfully. Don’t punish them for accidents, just calmly clean up the mess. Some key litter training tips include:

  • Use an appropriately sized, low-sided litter box kittens can easily enter.
  • Use a litter material suitable for kittens to dig and bury in.
  • Keep the box clean by scooping daily.
  • Use treats and verbal praise to positively reinforce litter box use.
  • Be patient and consistent to establish good lifelong habits.

With time, repetition and positive experiences, kittens learn that the litter box is the right place to eliminate indoors.


Litter boxes offer a convenient way for indoor cats to relieve themselves. According to the ASPCA, most cats prefer eliminating in loose, sandy substances that allow them to dig and cover their waste (https://www.aspca.org/pet-care/cat-care/common-cat-behavior-issues/litter-box-problems). Litter boxes provide an ideal environment that satisfies this natural instinct. Without litter boxes, cat owners would have to let their cats outside frequently or deal with cat waste around the house.

For cat owners, litter boxes are much more convenient than letting a cat outside to do their business. Litter boxes can be placed in an out-of-the-way location inside the home. Owners simply have to scoop waste out of the box regularly. This saves them from having to follow the cat outside multiple times per day or deal with waste around the yard.

Litter boxes are designed to contain odor and mess inside the box. They come in covered and hooded varieties to prevent litter scatter. High-sided litter boxes also help keep litter contained (https://modkat.com/blogs/modkat-purrr/what-are-the-benefits-of-an-enclosed-litter-box). For owners, this means minimal effort to keep their home clean and odor-free. Self-cleaning litter boxes offer even more convenience by automatically removing waste after the cat uses the box.

For indoor cats and owners, litter boxes offer the perfect solution for easy waste management. Both cats and owners benefit from the convenience they provide.


Outdoor access exposes cats to many diseases and parasites. According to Cats and the Perils of Outdoor Living | VCA Animal Hospitals, cats that go outside are at greater risk of contracting fleas, ticks, lice, ringworm, and other parasites that can make them itchy or ill. Stray cats may also spread these parasites to indoor cats if they come into contact.

Viruses like feline immunodeficiency virus (FIV), feline leukemia virus (FeLV), and rabies are more common in outdoor cats as well, according to Uncontrolled Outdoor Access for Cats: An Assessment of …. FIV weakens the immune system, making cats prone to infections, while FeLV causes anemia, immunosuppression, and cancer. Rabies, contracted through bites from rabid animals, is fatal once symptoms appear.

Keeping cats indoors protects them from these contagious and potentially dangerous diseases. Indoor cats live on average 10-15 years, while outdoor cats live on average 2-5 years, according to the American Humane.


In summary, there are several key reasons why pet cats use litter boxes indoors rather than eliminating outside:

– Domestication – Cats have evolved to live closely with humans indoors and use provided litter boxes.

– Territory – Cats instinctively avoid soiling their territory and living spaces.

– Instinct – Using litter boxes comes naturally to cats and leverages their instinct to dig and bury waste.

– Smell – Litter boxes contain and control odors better than eliminating outdoors.

– Cleanliness – Litter boxes help keep cats and homes clean.

– Training – Litter boxes are where cats are taught by owners to eliminate.

– Convenience – Litter boxes are always available regardless of weather conditions.

– Health – Litter boxes avoid exposing cats to diseases and dangers outdoors.

In closing, litter boxes provide an ideal indoor elimination solution that aligns with cats’ natural behaviors and modern domestic life.

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