Top 20 Reasons to Keep Cats Indoors

Plus How to Create the Purrfect Cat Enclosure (aka Catio)

Top 20 Reasons to Keep Cats Indoors

Discover the myriad benefits of keeping your feline friends indoors, ensuring harmony between wildlife and human communities while keeping your cats safe and healthy.

SECTIONS: to protect wildlife and humans, to protect the cats themselves, how to create the purrfect cat enclosure (aka catio)

To Protect Wildlife and Humans

Cat Killing a Rabbit

  1. Outdoor domestic cats are a recognized threat to global biodiversity. Cats have contributed to the extinction of 33 known species and continue to adversely impact a wide variety of other species, including those at risk of extinction. The International Union for the Conservation of Nature (IUCN) lists domestic cats as one of the world’s worst non-native invasive species.
  2. The top human-caused threat to birds in the U.S. and Canada is by domestic cats, which number well over 100 million in the United States. Cats kill approximately 2.4 billion birds every year in the U.S. alone. (source)
  3. A wide variety of wildlife, including birds, mammals, reptiles and insects are killed by cats. Studies conducted at the Wildlife Center of Virginia found that 84 different species of wildlife were brought to the center after being injured by a cat — 21 species of mammals and 62 bird species.
  4. Even if the bird or other animal escapes, they often die later. Cats carry bacteria in their mouths that overwhelm small animal immune systems. Injuries and a high degree of stress usually kill a small bird or mammal even after it escapes the cat.
  5. A significant number of wildlife victims are parents defending nests and fledglings, meaning that not only was the individual bird lost, but also more than likely her young as well.
  6. The mere presence of cats outdoors is enough to cause significant impacts to birds. Because cats are recognizable predators, even brief appearances near avian nest sites leads to at least a doubling in lethal nest predation of eggs and young birds by third-party animals and reduces by a third the amount of food brought to nestlings.
  7. House cats are considered "super predators" because:
    • they are an introduced predator (so wildlife has not evolved to defend themselves)
    • they exist in unnaturally large numbers, far greater than any natural predator
    • they are prolific breeders and tolerate other cats in their territories, so large numbers are maintained
    • many have a constant food source and are often more fit than natural predators
  8. Cats are also harming native predators. In Maryland, a study showed that due to cats overhunting chipmunks, the natural prey of many raptor species, the Cooper's Hawk (Accipiter cooperii) population struggled to find food and had to switch to preying on harder-to-catch songbirds, which lengthened their hunting times and increased their nestlings mortality rate. (source)
  9. Cats are the most common spreaders of the parasite toxoplasmosis gondii. Infection can lead to neurological problems, and sometimes death, in both wildlife and humans. Cats have been found to spread the disease widely, even in remote areas, through defecation. Human infections may cause eye lesions, deafness, seizures, mental retardation, blindness, schizophrenia, Alzheimer’s Disease, autism, obsessive compulsive disorder, memory loss, multi-organ failure, and even death. As many as 74% of all domestic cats in the United States will be infected by T. gondii during their lifetimes. (source and source)

To Protect the Cats Themselves

Cat Killing a Rabbit

  1. Cats who are kept indoors live an average of 10 to 15 years - outdoor cats live on average 2 to 5 years (source).
  2. Outdoor cats are at risk of being:
    • wounded in fights with other animals (many times resulting in dangerous abscesses)
    • hit by cars (an estimated 5.4 million are hit a year)
    • eaten or injured by a predator such as owls, raptors, coyotes or dogs
    • killed by inadvertently ingesting poisons such as antifreeze, rat poisoning or toxic plants
    • treated cruelly by animal abusers
  3. It’s harder for owners to identify health problems early (such as urinary tract disorder, renal failure due to old age, genetics or ingesting poison, and disease), before they become life threatening. When a cat is sick or injured, their natural instinct is to hide in silence because this is their primary defense mechanism from predators.
  4. Even long after application, lawn chemicals and their residue can have a negative impact on your cat. He can easily absorb the toxins through his paws, lick them off his fur, or ingest them by eating grass. Even if you don't use these products in your own yard, your neighbors might. Out of 30 commonly used pesticides, 19 are linked to cancer, 13 with birth defects, 21 with reproductive effects, 26 with liver or kidney damage, 15 with neurotoxicity, and 11 with endocrine disruption (source)
  5. Cats can be exposed to infectious diseases such as:

Bird Flu Warning

"...Domestic cats can be highly susceptible to HPAI A (H5N1) virus. Cats that have outdoor access should be monitored to avoid potential exposure to and consumption of dead wild birds." (source: Newsweek)

  1. Cats can get fleas, ticks, ear mites, intestinal worms, and ringworm.
  2. Cats can be picked up by animal control or a neighbor, and if missing identification, can be euthanized or adopted. Only 3% of cats turned into shelters make it back to their owners.
  3. Cats can get trapped inside structures such as garages, sheds, basements, or vehicles. They can also climb under the hood of cars and get injured or killed when the car is turned on.
  4. If cats are chased, they sometimes don't return home and can end up as a stray. (source)
  5. Cats can be endangered by sudden cold or stormy weather. They are especially at risk of hypothermia. (source)
  6. Trees can be a source of some danger for cats who climb to a place where they are afraid or unable to climb down. A cat may eventually become too weak to climb down, and after a point, even if rescued, may die later of starvation, dehydration, or exposure. (source)

How to Create the Purrfect Cat Enclosure (aka Catio)

How to Create the Perfect Cat Enclosure (aka Catio)

Catio's are the perfect way to help your outdoor cat adjust to an indoor lifestyle. There are a number of commercially built catios - or they can be built by hand (DIY plans: Catio Spaces). Below are some fun features to add to an enclosure to keep your cat active and happy. Select used products or materials whenever possible.

  • Climbing Structures: Cats adore vertical spaces. Install shelves, platforms, ramps, and cat trees in different heights to satisfy their natural climbing instincts.
  • Scratching Posts: Provide a variety of scratching posts or boards to help cats maintain their claws and mark their territory.
  • Hammocks and Perches: Comfortable resting spots like hammocks, perches, and cozy beds let cats relax while enjoying the view.
  • Hideaways: Cats love to retreat to cozy spots. Add enclosed hideaways like small cat houses or cubbies for them to feel safe and secure.
  • Toys and Playthings: Hanging toys, strings or wind chimes, feather wands, balls, and puzzle toys can keep cats engaged and active.
  • Plants: Non-toxic plants like cat grass or catnip can be placed in the catio. Some cats enjoy nibbling on greens.
  • Water Features: Installing a cat fountain inside or a rain chain outside the enclosure can add captivating movement.
  • Bird Feeders and Squirrel Feeders: Cats love to watch birds and squirrels. Install feeders near the catio to provide entertainment.
  • Climbing Nets or Ladders: Nets or ladders can provide additional climbing opportunities and challenges.
  • Sunbathing Spots: Make sure to have spots where cats can bask in the sun and enjoy the warmth.
  • Different Textures: Include various textures like soft rugs and sisal surfaces to keep their paws and minds engaged.
  • Window Perches: Place perches near windows so cats can watch indoor activities as well as the outdoor world.
  • Tunnels: Adding tunnels can give cats a sense of adventure and a space to play and hide.
  • Digging Elements: Consider elements like sand or a designated digging area for cats to dig and explore.
  • You!: Set a chair inside for visits.


The impact of free-ranging domestic cats on wildlife of the United States (nature communications)

Cats and Birds (American Bird Conservancy)

Study Documents Dramatic New Impacts To Birds From Outdoor Cats (American Bird Conservancy)

Indoor Cats vs. Outdoor Cats (American Humane Society)

Keeping Cats Indoors Isn't Just for the Birds! (American Bird Conservancy)

A Contaminated Environment (American Bird Conservancy)

Wild and feral cats found to shed more toxoplasmosis parasites in areas densely populated by humans (

JWM Study: Domestic Cat Attacks Cause Variety of Wildlife Deaths (The Wildlife Society)

Cats Pass Disease to Wildlife Even in Remote Areas (ScienceDaily)

How Different Strains of Parasite Infection Affect Behavior Differently (ScienceDaily)

Should You Have an Indoor Cat or an Outdoor Cat? (WebMD)

The Top 5 Ways that Outdoor Cats Become Lost (UnderCover Pet Houses)

Pet Statistics (ASPCA)

How Long Do Cats Live? (catster)

Five Most Dangerous Cat Diseases (Animal Planet)

20 Reasons to Keep Cats Indoors (Friends of Felines' Rescue Center)


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