By the end of this week, more than 70 school districts across the Pittsburgh area will be back in class. With every school bus that rolls down the street, pets are left behind after a summer of stimulation, often causing pet depression.

"They do sense the change in energy. You know, all the kids are leaving the house. They're used to the attention, the constant attention," said Dr. Mike Hutchinson, a Pittsburgh-area veterinarian and expert on animal health and behavior.

Suddenly, it's quiet.

"You'll see yawning. You'll see body shaking. You may see them change their own habits," dog trainer Chrissy Joy said.

"They'll start whining more. They'll get clingy," Dr. Mike said. "(Pets will) just stop eating, and they'll just get mopey, and so we have to pay attention to it."

Not all pets will experience the void. Dogs are more susceptible than cats, but there are things you can do.  

Extra attention for your pet

Both Dr. Mike and Joy say not to ignore the change in mood.

"What's going to happen is the dog's energy is going to manifest somewhere else, and that could be your couch, that could be your TV remote, or your favorite pair of shoes," Joy said.

There is a remedy, however. Introduce them to a new normal.

"Time is the best gift you can give to your pet," Dr. Mike said. "Go walk with them in the morning, before you go, if you have time."

"If not, as soon as you get back, spend 15-20 minutes with them. Give them that attention," Dr. Mike said.

Keep your pet occupied

In between that time, give them a treat that will occupy them for a while when you leave.

"A good one of those kong toys that you can fill up, you know, put peanut butter on one end, put it in a cup, add some low salt chicken noodle soup, and freeze it," Dr. Mike suggested.

Joy suggests trying dog puzzle toys that contain treats and turning on dog TV while you're gone.

"With music, it's scientifically proven to relax your dog and to provide sort of a stimulation that's not going to make them nervous, but maybe make them like feel that they're not alone, comfortable," Joy said.

Dr. Mike says if they don't bounce back after a couple of weeks, see your vet. There could be something else going on.

Some dog breeds are more prone to depression than others - those breeds that are more energetic and used to herding kids. Australian Shepherds, Border Collies, and German Shepherds will miss the kids the most.