Which of the following is NOT a sign of diabetes in dogs?

Frequent barking is not a recognized sign of diabetes in dogs. Diabetes mellitus in dogs is characterized by specific symptoms that stem from the inability to regulate blood sugar levels effectively. Excessive thirst, known as polydipsia, occurs as the dog’s body attempts to dilute high glucose levels in the bloodstream, prompting them to drink more water. Increased urination, or polyuria, is another common symptom, as the excess glucose in the blood spills over into the urine, drawing more water and resulting in more frequent urination.

Lethargy is also associated with diabetes, as the lack of insulin or the body's inability to use it can lead to decreased energy levels. In contrast, frequent barking does not correlate with the physiological changes experienced by a dog suffering from diabetes and can result from a variety of other behavioral or environmental factors. Therefore, selecting frequent barking highlights a lack of connection to the specific medical condition of diabetes.