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I Drink Therefore I Am (Importance of moisture in cat diets)

Fuji in the tub

Cats evolved to get dietary moisture from their food, or fresh meat.

Most domestic cats eating dry kibble need more moisture than they’re getting. In the last few years, people have become more aware of the importance of keeping cats well hydrated.  The moisture provided by a primarily wet diet has been shown to prevent urinary tract and kidney problems, among other health benefits.

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Dogs and people experience thirst when their bodies are about 4% dehydrated, but cats do not feel thirsty – and seek out known water sources – until they are very dehydrated, about 8%. Many mammals will die if they reach a 10% dehydration level.

You can lead a cat to water, but…

Cats require water in their food to remain adequately hydrated. Because they evolved in the dry climates of the near east, cats’ bodies are particularly adapted to get moisture from their food instead of by drinking liquids. As strict carnivores, prey was their primary water source and at 65-75% water it provides plenty of hydration. Cats have not developed a strong thirst drive, so they are not natural drinkers. Cats have to be dehydrated before they go to a known water source to take a drink.

Eight glasses a day = ?

People are told to drink eight glasses of water a day to stay healthy and hydrated. For cats, a general guideline is that they need water that equals 2.5 times the amount of food they eat. So if a cat eats 4 ounces of dry kibble each day, he should be drinking 10 ounces (1.25 cups) of water. Cats need more when their environment is hot, they get a lot of exercise, or if they’re lactating.

A cat gets it’s body water in three ways: from the natural moisture in the food he eats, from digesting food (water molecules are released as nutrients are broken down), and from drinking water voluntarily.

Keep in mind that giving cats a little extra water never hurts, but giving them too little water can cause serious health problems.

Increase canned and raw food

The best way to increase a cat’s moisture intake is by feeding high-quality canned and/or raw food diets. The difference in moisture content of dry kibble vs. wet food is about 60%. A cat’s natural prey diet, such as a mouse, contains 65-75% water. Dry kibble cat foods contain only about 7-10% water. Canned cat foods contain around 78% water. Raw foods contain about 60-75%.

Cats eating canned or raw food are likely to lap up any additional water mixed into their food, so adding a few tablespoons of water is an excellent approach.

Rotate watering holes

Another excellent way to increase water is to place bowls of water in places that are a bit unexpected in their environments. Put a new water dish in a windowsill for a few days, then move it to a coffee table for a couple days, then place it near a scratching post or on a kitchen counter. Moving the water dish keeps the cat interested in his environment. (Aside: one of my cats has low vision so I keep two water dishes in predictable places while I move other water dishes around. I also have to be more careful about placement, so she doesn’t accidentally trip over a water dish placed in a surprising place.)

If cats discover water in an unusual place during their daily explorations, their natural instinct is to investigate and drink. So providing more than one dish in more than one location in their territory increases the likelihood of a cat stopping to drink throughout his day.

Placing several water bowls at different locations around the house is especially important for cats eating dry kibble diets and for those who have a history of urinary tract or kidney issues.

Get fresh

Like people, cats prefer fresh water. How do you know if it’s fresh? Use your judgment. If you would not drink that water out of that dish, the cat shouldn’t either. The best guarantee is to change the water dish every day. Water harbors bacteria, parasites, and viruses – some of which are pretty dangerous. When we simply dump out the water and pour more water in the dish without washing the dish itself, icky particles are left on the dish.

If you don’t clean or replace a water dish daily, stick a clean finger into the dish and rub the bottom or side of the dish. If the sides of the bowl feel slimy, the bowl itself needs to be washed and replaced.

Use good vessels

The type of bowl holding the water is important, too. Ceramic and stainless steel are ideal because they are easiest to clean (it’s nearly impossible to get bacteria and odors out of plastic dishes) and they resist scratches, which harbor bacteria. Get rid of dishes when they look worn or scratched.

Some cats prefer shallow dishes and many prefer to have both water and food dishes elevated so that they don’t have to bend their heads to drink and eat.

Running water is also more likely to attract cats than standing water. It’s their instinct to seek out fresh water, and running water found in nature is usually more pure than standing water. Most water fountains for cats (and dogs) come with filters that purify the water as it cycles through the system.

Here’s a list of my favorite fountains:

  • Rain Drop Fountain by PioneerPet (very quiet motor, attractive, steel or ceramic models)
  • Premium Ceramic Cat Fountain by Petco (most economical option)
  • Perfect Pet Fountain by Glacier Point For Cats (complex filtration system)

Add flavor

For ill cats who desperately need to drink more water, an effective tactic is to add flavoring. This should only be done if there is also fresh, unflavored water available in another dish. Some of the ways to add flavors that can entice cats to drink are: bonito (fish) flakes, juice from canned tuna or clams, or a tiny bit of bullion or meat stock. Be careful when using bullion or meat stock – they are usually salted which can dehydrate the cat and sometimes include ingredients that can be toxic in large doses (such as garlic and onion).

Be aware of signs of dehydration

Cats do not feel thirsty enough to seek out known water sources until they are already dehydrated, about 8%. Many mammals will die if they reach a 10% dehydration level.

On a hot day, cats can become dehydrated within a few hours.

Severe dehydration isn’t common, but it’s important to know the signs. The most common symptoms are:

  • Dry skin
  • Less elastic skin
  • Dry nose
  • Sunken eyes
  • Dry foot pads
  • Dark urine
  • Constipation
  • Lethargy
  • Depression
  • Lack of energy

In the worst cases, cats can suffer from hyperthermia, which can lead to shock.

If this article is helpful & you’re able, please consider sending a thank-you tip/donation. Even small donations will help me keep my business running during the travel industry slump that has brought pet sitting to a screeching halt. Thank you! (FYI, for a sliding scale fee starting at $30, I offer consultations to help people solve their specific cat-related issues. Let me know what I can help you with.)

(Note: I do not accept payment for mentions or reviews of products and services that I write about on this site. Nonexclusive use of this article has been granted to other pet industry organizations but Kari Kells retains copyright.)

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