6 Signs of Illness in Your Pet (cont.)

Urinating More or Less Frequently

As Mitchell discovered with Monty, excessive thirst and urination might spell diabetes. But increased urination may also signal liver or kidney disease or adrenal gland disease.

With increased urination, housebroken pets might start wetting inside the house. Or a dog that usually sleeps through the night suddenly needs nocturnal bathroom trips, Meadows says. An owner might notice, too, that he or she is filling the water bowl more often.

In contrast, too little urination, or straining to urinate, often signals a urinary tract infection or bladder stones. These are urgent reasons, especially for cats, to see the vet, Meadows says. "Cats can get an accumulation of crystals in the bladder or stones in the bladder that create bladder inflammation and can cause blood in the urine." In male cats, this can plug up the urethra so that the cat can't urinate, which can become life-threatening within 24 hours.

"It's a hard thing to pick up because the only thing you might see is the cat making multiple trips to the litter box and just sitting there," Meadows says. Or cats that strain to urinate might change their habits and start urinating outside of their litter box, for example, into the sink or on bedding and furniture.

Sawchuk, who lives in Wisconsin, says that with the first snowfall, many people will report that their dogs have bloody urine. The problem may have existed for a while, but the owners didn't notice, Sawchuk says. "And now, [the urine] is in the snow and it's pink, so we get a lot of phone calls."