My cat Hector has thick skin.

I mean this literally. He lived for an unknown number of years on the streets of Bushwick (or thereabouts), and as my vet explained, adult male cats develop a tough dermal layer if they go long enough before getting neutered.

Sprouting from that thick skin is a soft, dense coat of orange fur. And every summer, the combo makes me wonder: Is he sweltering under there?

The anxiety spikes when I have to leave him home alone.

“Do I run the AC for a cat?” I wonder.

It seems irresponsible to leave that window-planted machine cranking, expelling heat into the rest of the city and stressing an overworked electric grid – not to mention the effect on the utility bill. But Lawrence Putter, a veterinarian at Lenox Hill Veterinarians, said it might be necessary.

“I would say if the heat is going to be in the 90s, then yes the air conditioner should be on,” Putter said.

But not all pets are created equal. So dog owners, take heed.

“Cats are smarter than dogs,” said Dr. Nuala McDermott, the owner and medical director at Pure Paws Hudson Square. “They tend to hide in cool spaces. Cats aren’t out there running the loop in Central Park.”

When the temperature surpasses 85 degrees, the chance of heat stroke goes up with it. The risk is especially acute for dogs, McDermott said, which thermoregulate by panting. They breathe hot air out, then they breathe hot, humid air back in, giving them no chance to cool down on the inside.

McDermott said a pug had come into her practice on Tuesday – just as a summer heat wave moved into the city – with a body temperature above 104 degrees – putting her at risk of heat stroke. The vets stuck her in a shower, pouring cool water over her stomach first, then her back.

“If you don’t have AC or if your power goes out, cooling the core temperature of the body with some not ice-cold, but cooling water,” is the best first step, McDermott said.

Although dogs tend to fare worse in the heat than cats, some kinds of dogs are at higher risk than others.

“Brachycephalics,” or dogs with short, smooshed-looking noses (like pugs) are particularly heat-averse, McDermott and Putter said, because a long snout is a dog’s key cooling mechanism.

There are also some items you can purchase to keep your pet friends cool.

“Hank wore a cooling vest to work today,” McDermott noted, pointing to her 10-year-old pug, who was splayed on the floor of her office. It’s a piece of animal fashion made of water-retaining fabric, so the owner can wet it, wring it out and then put it on their pet to keep them cool during a walk or commute. There are also cooling pads that cats can lie on.

The vets recommended keeping pets inside and in the shade as much as possible on hot days. In line with best practices from the ASPCA and the Humane Society of the United States, McDermott suggested walking dogs in the morning and evening when the sun isn’t at its peak, and advised pet owners to be mindful of hot pavement and to never leave their pets unattended in a car.

If you can’t escape the heat in your own home, the city also lists 16 cooling centers as pet-friendly. Thirteen of them are Petco stores, and three are elected officials’ offices.

In a Monday press release, the mayor’s office echoed McDermott’s advice.

“It’s important pets have access to clean, fresh water and stay cool inside,” Director of the Mayor’s Office of Animal Welfare Alexandra Silver said in the release. “We encourage people to walk their dogs early mornings and late evenings, and remind them that animals should never be left in cars.”

Or, they can follow Hank’s lead.

“Hank is the role model of what all dogs should be doing once it hits over 95 degrees in Manhattan,” McDermott said.

Dutifully, Hank was lying motionless on the floor.