We’re in the golden period of imprinting scent with our 9 week old litter of puppies. Unfortunately, today Alberta is experiencing record-breaking temperatures (1), combined with smoke blowing from forest fires in BC and Washington that is so thick it’s visible on satellite imagery. Throughout the day, the haze obstructs our view of the Rocky Mountains, and even closer landmarks in the urban skyline. Given how unpleasantly hot and asthmatic I feel, the puppies are surprisingly eager, inviting me to play. Even more than usual, it’s important to start each training session with a taste test, to test if the food reward is sufficiently rewarding for that pup on that day, in that environment. When a pup isn’t excited about his ball or his favorite food reward, it is probably more productive to take the day off. In our case, puppies found a 5 minute session in our indoor scent detection lab to still be enjoyable. Then we all revelled in the life reward of jumping in the kiddie pool.
Acclimatization is an important part of conditioning for scent dogs, and it’s tested during record-breaking temperatures. Don’t underestimate the time it takes for any animal’s body to adapts to massive changes in environment, such as extreme increases in heat and elevation. (If you’ve ever trained to run long distances in the Canadian winter and then compared with your performance when you arrive at a tropical vacation spot, you’ve experienced it yourself.) With appropriate support and care, you and your dog can learn to perform better in hot temperatures.
Please note that this blog focuses on thermoregulation and how heat acclimatization impacts sniffer dogs. If your dog is struggling in the heat in any way, seek shade, give plenty of water and contact your emergency veterinarian ASAP.
Let’s have a look at the underlying physiology of sniffer dogs exposed to heat stress (2). In normal conditions, 12-13% of the air the dog breathes in will reach their olfactory receptors. When working odor, active sniffing increases this by 2-3%. But in high environmental temperatures, the dog’s body involuntarily switches focus from sniffing for scent detection towards panting to stay cool. The heat load our dogs experience is 80% due to working skeletal muscles used in physical activity. (Vigorous exercise makes the dog much hotter than they would be resting on an uncomfortably hot day.) Dogs can either sniff or pant, but don’t usually sniff and pant simultaneously (8). While panting to reduce their body temperature, the dog’s pattern of breathing inevitably changes. Rather than the high frequency, closed mouthed sniffing we desire to enable prolonged scent detection, the dog exhales through his mouth in large, turbulent jets, which disrupt the normal flow of scented air through his nose for processing in detection work.
Gazit and Terkel compared the performance of bomb dogs while calm and lightly panting vs following exercise and heavily panting. Increased panting led to poorer explosives detection, and longer search times. When they compared performance in those dogs over time, they found that detection ability improved over time, beyond what could be explained by increasing fitness or motivation. The improved performance seemed to be caused by the dogs’ learning to sniff more while panting more. Further, “Such adjustment, expressed by the increasing sniffing frequency, can improve a dog’s work under strenuous conditions that can be taught by suitable training” (8).
So, how long does it take for sniffer dogs to acclimatize safely? In addition to gradually building cardiovascular fitness with age-appropriate activities, you may be surprised to learn that partial acclimatization can take 10 – 20 days and full acclimatization can take up to 2 months (see references below). Attempts to rush the process in a few days are likely to fail.
In summary, during short periods of record-breaking temperatures, it’s a reality that your dog’s scenting capabilities will decrease relative to cooler temperatures. Keep your scent detection sessions short, give plenty of water, wet your dog down, avoid the mid-day sun from about 11am – 2pm, and don’t be surprised when your dog is slower and less enthusiastic as he is challenged by the abrupt changes to his environment. As far as more strenuous physical exercise like running off leash, it may be better to temporarily decrease your dog’s physical activity, until the temperature returns to normal. This is especially true for brachycephalic breeds like the pug, whose anatomy always impacts thermoregulation through panting (learn more here (17). On the other hand, if you and your dog are preparing for upcoming scent detection work in extreme temperatures, start slowly and work up gradually to safely acclimatize to extreme heat over a few months.