Ask a Vet: Do Catios Eliminate Outdoor Risks for Cats?


More than a decade ago I began to write an Ask a Vet column for Catster. The column later morphed into a daily Vet Blog and has evolved into a series of articles written for Catster Magazine.

Much has changed at Catster and in my life during this tenure. But one thing certainly has remained constant. When I started writing, I strongly recommended keeping cats indoors. In the past decade my opinion on the matter has not changed in the slightest.

Allowing your cat to go outside is the veterinary equivalent to smoking. A person who allows his cats to go outside is begging for trouble.

Outdoor cats frequently are hit by cars. They suffer trauma when they fall off fences or out of trees. They get into fights with other cats, which can lead to abscesses and can result in infection with the feline immunodeficiency virus, also known as feline AIDS. They might get lost. They can suffer from hypothermia if they get caught in the rain. They are more likely be bitten by mosquitoes, putting them at increased risk of heartworm disease and allergic reactions. Foxtails might lodge in their hair, ears, nose, or eyes. Cats might be exposed to poisons. They might find additional food sources, leading to obesity and complicating medical conditions that require special diets. Eating from communal outdoor bowls can also expose cats to the feline leukemia virus. They might pick up parasites, including intestinal worms that can spread to humans, especially children, and cause serious disease.


They can suffer sunburn and are at increased risk of skin cancer. They might befriend neighbors who mistake them for strays and adopt (I hesitate to use the word “steal”) them. Outdoor cats often are the victims of predation — studies have shown that they are regular menu items for coyotes, mountain lions, and even birds of prey.

It’s not just cats who suffer the consequences from their outdoor escapades. Cats might be prey for some animals, but for many others they are predators. Environmentalists are rightly worried about the massive toll that outdoor cats take on birds, reptiles, and amphibians. Cats who defecate in children’s sand boxes can spread parasites to young people.


People who let their cats outdoors offer a variety of reasons for their decisions. Some believe that cats need fresh air. Others feel that cats benefit from social interactions with other cats in the neighborhood. (I disagree with that assessment — the interactions most cats have with each other outdoors largely consist of conflicts.) Some people say that their cats act up, urinate in the house, or become aggressive if they’re not allowed outside. And finally, some cats simply can’t be kept indoors — their desire to go looking for trouble is so strong that they routinely escape despite their owners’ best intentions.

In 2013, my editor at Catster asked me a question: Is It EVER Okay to Let a Cat Go Outdoors? My answer, essentially, was no.

But the other day the same editor posed a different question. Is it okay to let a cat go outside if he is confined in a catio?

This catio appears in Catification by Jackson Galaxy and Kate Benjamin.

A catio, in case you don’t know, is an outdoor enclosure for cats. Such enclosures range from small, simple, homemade structures that utilize wood planks and chicken wire all the way to enormous, professionally built, purpose-made Taj Mahals. Do I believe that they are safe for cats? Do they eliminate the various risks that plague outdoor cats?

Actually, if the structure is built well, the answer is yes.

A good catio will prevent a cat from wandering freely. The cat won’t get hit by a car unless a drunk driver careens off the road. A strong structure will protect a cat from predators, and prey animals generally will be safe from the cat. Confined cats can’t get lost or be abducted. The risks from foxtails are eliminated.

It is true that cats in catios may still encounter other cats. Free roaming or feral cats could walk right up to the enclosure and sniff a confined pet. But they won’t be able to fight through the fence. The sort of casual contact that could occur through a catio’s wire will not be sufficient to spread FIV or feline leukemia virus.

This catio in Seattle was featured in a catio tour similar to a home or garden tour in 2015.

In fact, a cat in a catio is almost as safe as a cat that is kept indoors. Almost. A few risks still exist. The sun’s rays will not be stopped by a mesh fence, so sunburn and skin cancer are still risks. Mosquitoes can still bite, leading to heartworm disease or allergic reactions. Hypothermia can be a risk on cold or rainy days. Respiratory infections might spread from neighborhood cats during through-the-fence encounters.

With the exception of respiratory infections (which usually aren’t life threatening), these risks are easy to manage. Provide shade in the catio, and don’t let the cat into it during peak sun hours. Avoid catio time at sunrise and sunset when mosquitoes are most active.

The biggest risk I see with catios occurs with improperly constructed ones. A shabby catio might develop gaps that allow cats to escape. Some folks mistakenly assume that tall walls will keep the cat inside. In fact, cats are remarkable escape artists so catios need to be fully enclosed with a roof made of fencing material or something solid. If the catio is well built, the risk is minimal.

If you want your cat to enjoy the outdoors, a properly build catio is in my opinion a good solution.

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