Dehydration means the body has lost more fluid than it's taken in. In pets, it can develop quietly—during hot weather, illness, or simply because they're not drinking enough. By the time a pet looks "really sick," dehydration may already be moderate or severe. Knowing the silent signs and how to do a quick check at home helps you act early and know when to call the vet.
This article covers signs of dehydration in dogs and cats, a simple at-home check (skin turgor), and what to do next—including ways to encourage your cat to drink more.
Why Dehydration Happens
Common causes include:
- Not drinking enough (low thirst drive, especially in cats)
- Vomiting or diarrhea (losing fluid faster than they can replace it)
- Fever or infection
- Heat stress or overheating
- Kidney disease (increased urination, less ability to conserve water)
- Diabetes (increased urination)
- Other illness that reduces appetite or increases fluid loss
Prevention focuses on ensuring access to fresh water, encouraging intake when needed, and addressing illness early.
Silent Signs of Dehydration in Pets
Early signs can be easy to miss:
- Less interest in play or exercise
- Slightly dry or sticky gums (normal gums are moist and pink)
- Mild lethargy or sleeping more than usual
- Reduced appetite
- Urine that looks darker or more concentrated (smaller, yellower spots in the litter box or on walks)
- Fewer or smaller pees than usual
As dehydration worsens:
- Clearly dry nose (not a reliable sign alone—some healthy pets have dry noses)
- Sunken eyes or dull expression
- Skin that stays "tented" when gently lifted (see below)
- Very sticky or pale gums; gums may be slow to pink up after you press them (capillary refill time)
- Weakness, collapse, or severe lethargy
- Heavy panting (dogs) or open-mouth breathing when not stressed
If you see severe signs—weakness, collapse, no urine for many hours, or repeated vomiting/diarrhea—seek veterinary care immediately.
The Skin Tent Test (Skin Turgor)
A simple way to get a rough idea of hydration is skin turgor ("tent test"):
- Dogs: Gently lift the skin over the shoulder or between the shoulder blades.
- Cats: Gently lift the skin over the shoulders or along the back.
- Release and watch how quickly the skin returns to normal.
- Normal: Skin snaps back within 1–2 seconds (or immediately in well-hydrated pets).
- Mild to moderate dehydration: Skin returns slowly.
- Severe dehydration: Skin stays tented or returns very slowly. By the time skin stays tented, dehydration is often already severe, so seek veterinary care.
This test has limitations: results can be misleading in older pets (reduced skin elasticity), obese or very thin pets, and breeds with loose skin. If the skin tents and stays up, your pet is likely dehydrated and may need a vet. Always combine it with gum moisture, energy level, and whether they're drinking and peeing.
Checking Gums (Capillary Refill Time)
- Normal: Gums are moist and pink. When you press a finger on the gum and release, the spot briefly turns white then pinks up again within 1–2 seconds (capillary refill time).
- Concerning: Gums may be dry or sticky, and capillary refill longer than 2 seconds may indicate dehydration or poor circulation. Very pale or blue gums are an emergency.
Check gums in good light; avoid doing this if your pet is stressed or might bite.
When to See a Vet
- Mild signs (slightly dry gums, less playful): Encourage drinking, offer wet food or tricks to increase water intake. If no improvement in a few hours or if you're unsure, call your vet.
- Moderate signs (skin tents, sticky gums, lethargy, reduced urine): Call your vet the same day. They may advise bringing the pet in for assessment and possibly fluids.
- Severe signs (weakness, collapse, no urine, repeated vomiting/diarrhea, very slow capillary refill): Emergency vet—dehydration can be life-threatening when severe.
Don't force large amounts of water by mouth; it can cause choking or aspiration. Let the vet give fluids if needed (under the skin or into a vein).
How to Help Prevent Dehydration
- Always have fresh water available in clean bowls (or a fountain for cats).
- Encourage drinking with multiple bowls, wet food, or water added to food.
- In hot weather or after exercise, offer water and avoid overheating.
- During vomiting or diarrhea, offer small amounts of water frequently and see the vet if it persists or your pet won't drink.
- If your pet has kidney disease or diabetes, follow your vet's advice on water access and monitoring.
The Bottom Line
Dehydration in pets can be silent at first—reduced energy, slightly dry gums, less urine. Use the skin tent test and gum check as a rough guide; if skin tents and stays up or gums are dry and refill is slow, contact your vet. Severe signs (weakness, collapse, no urine, heavy vomiting/diarrhea) need emergency care.
Prevention: fresh water always available, creative ways to get cats to drink, and prompt vet care when illness or fluid loss is involved. Keeping your pet well hydrated supports their overall health alongside a balanced diet—use our pet meal planner to get their daily portions right while you focus on water intake.
