November 18, 2025
Provided image/Shelby Wise
Working with her team at the Penn Vet Working Dog Center, Dr. Cynthia Otto discovered voluntary head dunks in water were the best way to cool off a dog.
When humans exercise, they work up a sweat that naturally cools them down. But dogs rely on panting to regulate their body temperature, and if they get too hot, this canine method doesn't really work.
This is a particular matter of concern for working dogs, who perform strenuous tasks like search-and-rescue missions. To help protect them from heat stroke, Dr. Cynthia Otto, the executive director of the Penn Vet Working Dog Center, spent years researching the best way to quickly cool an overheated pup. She and her colleagues found a trick that took as little as five minutes to teach and could keep K9s and pets alike safe on hot days — training a dog to voluntarily dunk its head in a bucket of water.
This technique brought down the core body temperature in its furry test subjects in the first 30 seconds after exercise, stopping the spike that usually follows physical activity. It has earned Otto a nomination for the American Kennel Club Canine Health Foundation's inaugural discovery of the year award. She is one of three finalists competing for the honor and the $10,000 prize that comes with it.
Veterinarians have long known that immersing dogs completely in water — in a pool or dunk tank, for instance — can cool them off. Otto, whom Netflix subscribers might remember from "Inside the Mind of a Dog," was interested in finding more practical solutions. What could animal handlers do when a pool or gallons of water were inaccessible? Watching dogs sniff out illegally poached ivory in Zambia, she said, greatly influenced her thinking.
She and her colleagues conducted two studies. In the first, they had dogs chase a ball or toy for 10 minutes, then tried cooling them one of three ways. Some dogs simply stood passively in the shade, others stood in a pool of room temperature water for 30 seconds and still more stood on a towel soaked in rubbing alcohol for 30 seconds. All of the pups then rested.
The researchers concluded that partial water immersion was the best option. While applying rubbing alcohol to dogs' paw pads, one of the only areas where they actually sweat, had some benefits, it also stressed the animals out. Their heart rates rose when they stood on the soaked towel, likely due to the alcohol's odor and/or irritating effects.
So the team struck out again. In the second study, Otto and her colleagues used four different cooling methods. They tried placing wet towels under the dogs' armpits, chemical ice packs on their necks, wet towels around their necks or incentivizing them to dunk their head in water with a toy or treat. The head dunk was the clear winner.
"When you cool their head, it cools the dog," Otto said. "It makes sense in the end, but it was a surprise. We weren't expecting the impact. And the cool thing about it is it's immediately translatable. We're talking to all sorts of people in the field who are now utilizing this to keep their dogs safe and cool."
Teaching a dog to voluntarily dunk its head in water is really just a matter of gradual exposure. As Otto and other vets explain in a video for the American Veterinary Medical Association, trainers and pet parents can start by placing a toy (such as a Kong with a treat inside) in an empty bucket or container. Step back and let the dog retrieve. Then, add a small amount of water to the bucket and put the toy back at the bottom. Let the dog grab it and repeat the process until the bucket is filled with enough water for a head dunk. Just make sure to choose a toy that won't float.
Owners and handlers should not attempt the head dunk on dogs that are struggling to breathe or have collapsed. These animals should receive total body immersion and veterinary care. Otto also stresses that the technique is voluntary. Pet parents shouldn't force it on their dogs if they cannot or will not voluntarily dip their heads in the water.
Otto has been pleasantly surprised by how quickly her training trick has caught on. Though she's already exploring new questions in veterinary science, she's hopeful the innovation will head off life-threatening heat strokes.
"I spent my first 20 years of my career at Penn in the emergency room," Otto said. "I would hope that there'll be fewer dogs that come in because of heat injury into the emergency room. That's what I want. I want dogs to be able to work and play and be safe at it."
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