Ohio wildlife has a myriad of adaptations to survive when the mercury starts rising in July and August. A highway of blood vessels in the ears of Eastern cottontail rabbits allow excess heat to dissipate; vultures excrete onto their unfeathered legs to increase heat loss by evaporation; and the cold-blooded Eastern box turtle, with no internal mechanism for cooling, relies on finding a more hospitable space by digging into the leaf litter and the soft earth beneath.
Dogs, such as foxes and coyotes, rely primarily on panting to cool themselves. Evaporating moisture from their mouth, nose and lungs takes heat away from the body. Think about when you step out of the shower and immediately feel chilly. The water evaporating from your skin is transferring heat. To mitigate the risk of overheating, many wild canids start to work the evening shift or become completely nocturnal.
It’s a little different in the world of our pets, because we control when our dogs take a walk or play fetch. As humans, we are covered from head to toe with 2 to 5 million sweat glands – no doubt a useful evolutionary tool allowing us to continue hunting when other predators had to rest. For our furry friends, sweating plays a very small role in temperature regulation. With that in mind, if the air temperature is too much for you, it is way too much for them, and is especially harsh on old and young dogs, overweight and “flat-faced” dogs like boxers.
A couple of years ago my dog, Foster, started panting excessively while we walked together on one of the first humid days of the summer. High humidity slows down the evaporation that allows the cooling to occur. The breathing was more frantic, fast and shallow and sounded harsher than usual. Although a lab mix, he doesn’t usually drool, but he had started to on this particular walk. Showing no desire to chase rabbits or squirrels, he had become sluggish. These are the early warning signs heading down the path toward heatstroke.
Home we went and cold water to drink, a cool tile floor and a fan. He’s now 12 years old and still going strong. It was a reminder that heatstroke is an emergency for dogs as it is for people, and symptoms can quickly progress into vomiting, collapse, seizures and finally, organ failure. A change in a dog’s body temperature by 4 degrees Fahrenheit can mean the difference between life and death.
The intensity and duration of exercise is key. My trusty companion and I take shorter, slower walks right before the sun goes down and always with plenty of water. It helps if there is shade from trees that do not block the breeze. If you walk your dog on pavement, try testing the temperature of it by placing your hand palm down on the surface for 10 seconds. If it’s too hot for your hand, it may burn your dog’s paws and the heat reflected off the surface will increase your pet’s core temperature. Walking on grass or unsurfaced trails will help greatly.
Have fun out there and enjoy the parks safely, knowing that your dog has more to deal with when it comes to beating the heat!
Nature Interpreter, Farbach-Werner Nature Preserve