How dogs and cats keep warm in winter and cool in summer

South Africa has the perfect temperate climate to keep dogs and cats safely comfortable during all seasons. However, in some parts of the country, it can get very cold in winter and very hot in summer. During weather extremes, we need to be aware of pets’ wellbeing: are they warm enough or cool enough? How do they keep themselves warm or cool themselves down, and what can we do to ensure they are not freezing or overheating?

In this article, we’ll explore the concept of thermoregulation in dogs and cats, and how this mechanism works. We can then answer your questions about pets’ thermoregulation and how to help our pets maintain their body temperature during hot and cold weather.

How do dogs and cats regulate their temperature?

Our dogs and cats are warm-blooded animals whose body temperature needs to be maintained at a steady heat of between 37.5°C – 39.2°C for dogs and 38.1°C – 39.2°C for cats. Thermoregulation is the involuntary process that controls this temperature equilibrium. A tiny ‘thermostat’ in the hypothalamus (at the base of the animal’s brain) tells the body when it’s getting too hot or too cold, and sets in motion processes that help the animal to either lose heat to cool down or to generate heat warm up.

How do pets cool down?

When they get too hot, both dogs and cats pant, expelling warm air out of their mouths and cooling their bodies. They may seek out shade, spread out on a cold tiled or cement floor or shaded patio, and seek out a source of water to help cool them down. They shed heat primarily through panting, but also release a little heat by sweating through their paw pads. When it’s hot, their blood vessels dilate (vasodilation) and blood is directed away from their core and towards their skin. It is released via radiation – so their skin will feel warm to the touch.

Important note: Even double-coated dogs like huskies, border collies, German shepherds and Pomeranians know how to keep cool in summer. Their double coat insulates their bodies with cool air, keeping the heat out during the summer months. Never shave your double-coated dog for summer or at all. This can severely impact their ability to thermoregulate and they can end up overheating.

How to tell if your dog is overheated

A dog that is experiencing discomfort or even distress because of being too hot will show some unmistakeable signs:

excessive panting
drooling
bright red gums and tongue
rapid heartrate
restlessness/pacing
increased signs of anxiety like whale eyes
seeking out a shaded area/digging a hole in the ground for a cool place to lie
lack of energy/lethargy

If you are outdoors during the summer and see these signs in your dog, immediately move them to a cooler environment, offer fresh, cold water, and refrain from further exercise until they have calm down and cooled down. A dog that is overheating can very quickly suffer from heatstroke if they battle to cool themselves down fast enough.

How to prevent pets from overheating

In many instances, you control your pets’ environment, so it pays to be aware of how they can be impacted by the temperature – especially in summer. In order to prevent overheating or heatstroke:

never ever leave your pets in the car, even if you’ve parked in the shade. The interior of a vehicle can quickly become hotter than expected!
never walk pets in the hottest part of the day
never over-exercise pets at the height of summer – walk or play with them during the cooler parts of the day and take frequent breaks
always have fresh, cool water available for your pets

How do dogs and cats keep warm?

When dogs and cats get too cold, they may shiver to generate heat and also experience piloerection – the mechanism in the skin that stands their fur on end (like goosebumps), which traps their body heat close to their skin. Curling up into a tight ball also helps to retain heat and prevent it from escaping via their extremities. Aside from this self-generated heat, they seek out other sources of heat like a sunbeam, a heater, their human owner, or an animal companion to help keep them warm.

How do I know when my dog is cold?

When the environment is cold, your dog’s brain detects that they are getting cold and sends signals to their skin, muscles, blood vessels and other organs so that they can go to work to preserve what little heat is available and to generate more heat. There are external signals that you can see and feel if you are concerned about your dog getting cold:

their extremities are cold to the touch (ears, paws, tail tip)
their nose may be cold and dry
they may stand with a hunched posture and tucked tail
they may be visibly shivering
they may lie down in a tight ball – reluctant to get up and move around

How to warm up a shivering dog

If your dog is getting very cold and shivering to generate heat, there are many helpful things you can do to warm them up. Make sure their bed is warm – a nice, thick, high-quality bed that is raised off the floor can keep your dog warm. If you can’t raise their bed, place it on a carpet or another insulating surface. Cover your dog with a blanket or dress them in a dog jersey or pyjamas. The extra layers will help them to trap body heat close to their skin and keep warm during winter. A heating pad, hot water bottle or microwavable beanbag can also help to warm up your dog; just ensure that they are not too hot so as to burn your pup.

These warming solutions are very much dependent on what type of coat your dog has: short and flat, long and thick, or something in between. Dogs with thin skin and low body fat – like the greyhound, Italian greyhound, and Chihuahua – will need more insulation in wintertime to ensure they do not end up shivering and cold. Dogs with thicker skin and fur – such as the border collie, Samoyed, Siberian husky, Belgian shepherd or chow chow – will not need much by way of additional layers and blankets, because they are adapted to much colder weather than we experience in South Africa. However, always be cognisant of your dog’s behaviour and body language to ensure that they are comfortable. It is best for their wellbeing to want to warm them up, but make sure that they do not overheat.

How do I know when my cat is cold?

Similar to dogs, cats also display symptoms of feeling cold, which you will be able to identify just by touch and by their behaviour. Cats’ smaller size and higher body temperature mean that when they get cold, they feel it acutely, and their body will go into heat-preservation mode rather quickly. Cats will show symptoms of cold such as:

cold extremities (ears, nose, paws and tail tip)
shivering
less willingness to exercise and move around
hunched/arched standing position
raising one paw off the ground (especially when they are standing/sitting outside)
increased lethargy
sleeping more often
curled up in a tight ball, retaining heat around their belly

Your cat’s ears, nose and tail tip will be cold because their blood vessels there constrict, retaining their blood (and heat) closer to their vital organs to keep them functioning at the optimal temperature. They will be less active in order to preserve their body heat and energy. In wintertime, cats may tend to eat more to give them the additional calories required to maintain their body temperature. So, it’s important to keep an eye on your cat’s body condition during the winter, and to try to keep them warm.

How to warm up a cool kitty

You may notice during winter that your cat seeks out warmth: the sunny spot in the window, the cosiest position near the fireplace or heater, or on your lap. Your cat needs a direct source of heat to warm up, so either place a blanket or two in her bed so that she can make a ‘nest’, or place a blanket over her when she’s curled up on the couch. It may also help to warm up her meals (but not too hot).

If your cat is getting very cold (or you have a senior cat whose thermoregulation may not be as efficient anymore), they may need to have a hot water bottle, heating pad or microwavable bean bag placed under a blanket, on top of which they can then lie down and curl up. Despite your cat feeling lethargic from the cold, it will be very helpful to exercise them in order to warm them up. At first, they might seem as though they don’t want to be active, but with a bit of coaxing and motivation (with a treat or an exciting feather wand toy), they will greatly benefit from the activity, which will help to warm them up and keep their joints and muscles active and supple.

If you have feral or outdoor cats, you can keep them warm by providing outdoor shelters. Each shelter would need to be insulated, waterproof, and out of the elements. It’s preferable to have a small entrance so that the inside of the shelter can retain warmth.

How to prevent hypothermia in pets

Dogs and cats can become hypothermic (too cold) in winter if they cannot maintain an adequate body temperature. Since you can control their environment, make sure that your pets:

are never left outdoors during winter – all pets should have a warm, comfortable place to sleep indoors
never walk on icy ground – if the ground is too cold in winter, rather walk your dog or play with your cat outdoors during the warmer parts of the day
have adequate bedding and blankets
are well-fed, but not overfed (obesity is not a solution for the cold)
are supervised at all times if they are lying next to a fireplace, or gas or electric heater

Keep your pets warm this winter and remember: if it’s too cold outside (and inside) for you, it’s too cold for them. Give your dogs and cats an extra snuggle during the winter months and you’ll warm their hearts as well as their bodies!