My sister planned to leave her dog, Mackinac, at my parents’ house while she drove my mother to the airport, but Mackinac was having none of it.

He stood at the back gate at 6 a.m., barking loudly in the vicinity of the neighbor’s bedroom window, so the plan was quickly changed to include him in the ride. He has also been known to lie at that same gate and howl, waiting for my sister to come back to get him when she runs a quick errand. He loves both of my parents and is always happy to visit them — as long as my sister is there, too.

The ASPCA says that behaviors associated with anxiety disorders in dogs do include barking and howling but can also include pacing or digging and chewing in an attempt to escape. These behaviors may begin as his owner prepares to leave or within a short time after his owner has left and may not be simply the result of poor training. They may be caused by an underlying anxiety that can be extreme and result in injury to the dog and damage to the home, particularly near doors and windows. Separation Anxiety may be triggered by a change in the animal’s residence, human family situation or even a change in his schedule.

We’ve all heard the stories of a pet that lies for days on the grave of his late owner or who stops eating when another animal dies. Companion animals can grieve a loss and suffer from depression much in the same way that humans do, displaying both apathy and a loss of appetite.

According to Psychology Today, animals can also suffer from Obsessive Compulsive Disorder (OCD) or Canine Compulsive Disorder (CDD), with symptoms including incessant digging, grooming, and chasing of his tail, shadows or imaginary flies.

As with humans, mental illness can be something with which an animal is born, or can be the result of trauma, disease or aging. If your pet begins to show any change in typical behavior, the first step is to consult your veterinarian who can check him first for any physical ailments that may be causing the behavior. Apparent apathy and lack of appetite may not be depression, but rather the result of an infection or injury causing discomfort. Excessive licking may not be OCD/CCD, but rather an allergic reaction to fleas or something he’s eaten or with which he has come into contact.

When the physical causes have been ruled out and the circumstances suggest that the cause may be psychological, your vet may prescribe medication to help ease the symptoms. While these medications may be identical to those prescribed to humans, never try to make your own diagnosis or give your pet medicine intended for a human unless directed by your veterinarian. Some human medications are toxic to pets and even those that can be helpful must only be given in the proper dosages and under a professional’s guidance.

— To adopt a dog or cat, please visit the Athens-Limestone Animal Shelter at 1701 U.S. Highway 72 (behind Limestone Veterinary Clinic,) visit our Facebook or page or call us at 256-771-7889.

E-mail your questions story ideas to me at PetsAndPeople@charter.net; and I’ll check with the experts (veterinarians, animal behaviorists, etc.) and get back to you in a future column.