Signs of Dehydration in Dogs and Cats (and How to Prevent It)

From subtle behavioural changes to serious health risks, dehydration in pets can happen fast, especially during Australia’s scorching summers. 

While a bit of panting or resting in the shade might seem harmless, these could be early signs your pet is not getting enough fluids. Left unchecked, dehydration can lead to heatstroke, organ damage, or even become life-threatening. This vet-approved guide explains how to recognise dehydration early and offers simple, practical tips to keep your dog or cat safely hydrated all year round.

Dogs and cats are unable to tell us when they feel thirsty, and by the time they begin to act differently, they may already be mildly dehydrated. Being alert to the subtle early signs can help you take action before it becomes a medical emergency.

Common signs of dehydration include:

• Sticky or dry gums
• Sunken eyes
• Lethargy or low energy
• Reluctance to eat
• Reduced skin elasticity
• Increased heart rate
• Excessive panting (especially in cats, which is always abnormal)

Even mild dehydration can impact your pet’s comfort, mood, and energy. Early intervention is crucial, especially during warmer months, after exercise, or during illness.

Dehydration can occur for many reasons, not just during hot weather. Recognising the underlying causes is key to prevention.

Heat and Humidity

Warm climates like Australia’s put dogs and cats at high risk of dehydration. Pets can overheat quickly during outdoor activity or in hot environments.

Illness or Infection

Conditions that cause vomiting, diarrhoea, fever, or infection can lead to rapid fluid loss. Dehydration can set in long before other symptoms appear serious.

Medications

Some medications, such as diuretics, anti-seizure treatments, or certain heart drugs, can increase your pet’s water requirements.

Chronic Health Conditions

Pets with kidney disease, diabetes, or hormonal imbalances such as Addison’s disease may have a reduced ability to retain fluids.

Mild dehydration may be treated at home with close monitoring and increased fluid intake. However, moderate to severe dehydration needs prompt veterinary attention.

Contact your vet immediately if your pet shows:

• Vomiting or diarrhoea that lasts longer than 24 hours
• Gums that are pale, dry, or sticky
• Weakness, collapse, or extreme tiredness
• Rapid or laboured breathing
• Refusal to drink water for more than 12 hours
• Panting in cats, which is a medical emergency

You can do a couple of quick checks at home to see if your dog or cat might be dehydrated. These tests are simple and can help you decide whether it’s time to call the vet.

1. Check Their Gums

Gently lift your pet’s lip and touch their gums with your finger. 

If the gums feel smooth and moist, your pet is likely well-hydrated.

If they feel dry, sticky, or tacky, your pet may be dehydrated.

2. Try the Skin Pinch Test

Lightly pinch the skin at the back of your pet’s neck or between the shoulders, then let go.

If the skin quickly snaps back into place, that’s a good sign.

If it stays pinched or moves back slowly, it could mean your pet is low on fluids.

Some pets are naturally more vulnerable to dehydration due to their breed, age, or health status. These animals should be monitored more closely, especially during hot weather, after exercise, or when unwell.

Dog Breeds and Types at Higher Risk

• Flat-faced breeds such as Bulldogs, Pugs, Boxers, and Boston Terriers
• Senior dogs, whose thirst response may be reduced
• Puppies, especially during weaning and growth periods
• Working and highly active breeds like Border Collies, Kelpies, and Retrievers
• Dogs with chronic health conditions, including kidney disease, diabetes, or Cushing’s disease

Cat Breeds and Types at Higher Risk

• Flat-faced breeds such as Persians, Himalayans, and Exotic Shorthairs
• Senior cats, who may drink less due to reduced kidney function or mobility
• Kittens, particularly those not yet eating or drinking consistently
• Cats with ongoing health issues like kidney disease, hyperthyroidism, or diabetes

Ensure these pets always have easy access to clean water and a cool, shaded place to rest. Regular monitoring and encouraging drinking habits can go a long way in preventing dehydration.

Fresh water should always be available, but some pets need a little extra help to stay properly hydrated. Whether you’re dealing with hot weather, travel, illness, or a naturally low-drinking pet, the right tools can make a big difference. These vet-recommended products are designed to support hydration and make it easier to meet your dog or cat’s daily fluid needs.

Hydration Support for Dogs

Dogs tend to lose fluids quickly through panting and exercise, so having hydration tools on hand is especially important during summer or after activity.

Recommended options include:

1. Collapsible Water Bowls

Ideal for walks, hikes, or car trips, these lightweight bowls fold flat for easy storage and clip onto your bag or leash. They’re hygienic, portable, and perfect for offering water on the go.

2. Electrolyte Supplements for Dogs

Useful during recovery from vomiting, diarrhoea, or heat exposure, these oral solutions help replace lost fluids and essential minerals. Two commonly recommended options are Jurox Lectade Oral Rehydration Therapy Sachets and Vetsense Rehydrate for Dogs, both designed to support rehydration when your dog needs an extra boost. Always speak to your vet before offering electrolyte solutions.

3. Dog Water Fountains

Many dogs are more likely to drink running water. A pet fountain keeps water fresh and encourages regular drinking, which is especially helpful for fussy or inactive drinkers.

Hydration Support for Cats

Cats naturally drink less water than dogs, so supporting their hydration through food, supplements, and the right water setup is essential. These vet-recommended options can help increase your cat’s daily fluid intake, especially if they eat dry food or have urinary or kidney concerns.

Recommended options include:

1. Hydration Supplements

These liquid supplements are designed to increase your cat’s total water intake in a palatable and easy-to-administer format. One popular product is Purina Pro Plan Veterinary Supplements Hydra Care for Cats, which is clinically proven to help cats drink more. It supports hydration and kidney health and is ideal for cats with low thirst or those prone to urinary problems.

2. Wet Food and Broth Additions

Wet food provides significantly more moisture than dry kibble, while broth toppers add hydration and flavour that encourage picky eaters to consume more fluids.

Vet-recommended wet food options and cat-safe broth toppers can be especially helpful for cats that rarely drink from their water bowl.

3. Water Fountains

Flowing water often appeals more to cats than still water. A pet water fountain mimics a natural running source, encourages curiosity, and can lead to more frequent drinking throughout the day.

Keeping your pet hydrated doesn’t have to be complicated. These simple, vet-recommended habits can help ensure your dog or cat gets enough fluids every day—no matter the season.

Make Water Easy to Access

Pets are more likely to drink when water is easy to find and appealing.

• Place multiple water bowls around your home and outdoor areas
• Keep bowls in quiet, low-traffic spots to reduce stress
• Clean bowls daily to remove slime and bacteria buildup
• Choose ceramic or stainless-steel bowls instead of plastic

Boost Fluids Through Food

Adding moisture to your pet’s diet is one of the easiest ways to increase hydration—especially for cats.

• Feed wet food regularly or mix water into dry kibble
• Add pet-safe broth toppers for extra flavour and hydration
• Use water-rich treats like seedless watermelon or cucumber for dogs

Use Tools That Encourage Drinking

Some pets need a little motivation to drink more, and a few simple tools can help.

• Offer water in a pet-safe fountain to provide fresh, flowing water
• Keep a collapsible water bowl on hand for walks or travel
• Add ice cubes to the bowl on hot days to cool water and make it more interesting

Watch for Subtle Clues

Sometimes your pet’s habits give you clues that their hydration needs aren’t being met.

Dehydration can sneak up quickly, but it’s also highly preventable with the right care.

By knowing the warning signs, performing simple at-home checks, and making hydration a daily priority, you can keep your dog or cat happy, healthy, and safe — no matter the season.

And if something seems off? Don’t hesitate. A quick trip to the vet could make all the difference.

This article was written by Dr Jack Ayerbe