The Irish summer is here. The skies have been cloudless and blue, the sun's been shining, and the rain clouds have stayed away. The COVID-19 crisis means that we've all had to be socially distant from one another, but that hasn't stopped us from gathering in public places like parks, beaches and seaside promenades. People stand apart, speaking more loudly than before, and wearing facemasks in public.
While it's very pleasant to bask in the full heat of the sun, the Irish summer is not quite the same as the climate in more southern and eastern parts of Europe. When you are out in your garden, enjoying a barbecue or reading a book, the ambient temperature depends hugely on the presence of the sun. If the sun goes behind a cloud, or if for any other reason you are in the shade, it doesn't take long till you feel a chill, and you need to find some other source of heat, whether it's switching on a patio heater or putting on a cardigan. The ambient temperature in Ireland is just between 17 and 21'|C, while in Berlin it's 24 - 27'C, and in Bordeaux in the south of France it's 29 - 30'C. So despite the lovely sunshine, we still live in a temperate climate.
It's easy for humans to adapt to changes in ambient temperature: we can move to cooler or warmer areas, we can add layers of clothes (or take them off), and it's easy for us to make sure that we are in our optimal state of comfort. Humans very rarely become uncomfortably cold, or unbearably overheated. We are fortunate in that we are able to take steps to stop this from happening.
It's different for pets: animals don't have the same level of personal freedom as humans, and they can be placed in difficult and uncomfortable situations that they cannot escape from if we are not careful.
Different types of pets have different challenges. We generally allow cats the freedom to move where they wish to go, and they are good at finding cool spots on hot days if they overheat. Small pets like rabbits and guinea pigs need to be monitored carefully: hutches should be moved into hte shade on sunny days to stop overheating.
Of all our pets, dogs are the most vulnerable to heat stress. Most people are aware of this risk in sunny weather, but this is so important that it's worth repeating the essential messages.
Dogs cannot sweat: they lose body heat primarily by panting, breathing rapidly and repeatedly through their mouths (rather than their normal method of breathing at rest, through the nose). The tongue swells up as its blood supply increases and its blood vessels dilate. If you stop and watch a dog panting, you'll wonder how that huge tongue ever manages to fit inside their mouth when it's closed. This increase in size means that the tongue has an increased surface area, and as air rushes back and forth across it, water evaporates as vapour from its moist surface, drawing heat out of the blood, and hence out of the body.
This is an effective way of losing body heat, but it depends on dogs being in an immediate environment that is cool enough for the heat to be lost. It also depends on the dog having a plentiful supply of fresh water, to keep their tongue moist.
If a dog is in a warm space (such as a car, or even a sunny back yard with no shade), their body absorbs heat more rapidly than it can be lost through panting. The result is the rapid onset of heat stroke, where the body temperature climbs steeply, the dog collapses, and without rapid intervention, coma and death can follow.
There are three other factors that often make things worse for dogs.
First, exercise. When dogs walk or run, their muscles produce heat: this happens to us as well, which is why people start to sweat when exercising. Dogs can't sweat, so they need to pant to get rid of this muscle heat. On a hot sunny day, they cannot pant enough to get rid of the combination of muscle heat plus heat absorbed through their skin from sunshine. When dogs are taken out for walks in the park or countryside on sunny days, they sometimes collapse and refuse to continue walking. They lie there, panting, and their owners often don't understand what's happening. This is heat stroke, and these animals need to be rapidly cooled down with cold water: it's a life threatening emergency.
Second, conformation. For dogs to lose heat effectively by panting, they need to have wide open airways that allow air to move rapidly across their tongues, in and out, in and out. So-called brachycephalic, or flat-faced breeds, such as Pugs and Bulldogs, often have narrowed airways that only allow restricted flow of air. The incidence of death from heat stroke is far higher in these types of animals. Their owners need to be especially aware of the need to keep them cool at all times.
Third, dogs with thick, heavy coats are more sensitive to overheating. Can you imagine if you had to wear a thick jersey all summer, even when out in hot sunny weather? If you have a dog with this type of coat, you need to work with your local professional dog groomer to ensure that the coat is suitably trimmed, clipped or thinned, to keep your pet as comfortable as possible.
Enjoy this sunshine, but please make sure that your pets enjoy it too. Don't let them overheat!