Winter weather can bring new challenges to pet ownership. There are a number of recommendations that the AVMA says are important to prepare you and your pet for the winter months.

You can read through the recommendations with the link above, but I just wanted to point out why some of these make so much sense with SCIENCE!

Why is a pet’s size an important factor to keep in mind when gauging their tolerance for cold?

The answer to this question comes down to a significant factor in many contexts: Surface-area-to-volume ratio.

Surface area to volume ratio says that the surface area (the outside covering of an object) increases at a square rate.  While the volume (the amount of space a thing takes up) increases at a cube rate. This means that the volume increases faster than the surface area.

This is important in chemistry and physics because, in most instances, reactions can only take place on the surface of objects. Increasing the surface area when compared to the size of the object generally speeds up reactions.

This is where your pet comes in. Dogs and cats are warm blooded and therefore get warmed internally. This warmth is gradually dissipated to the outside environment through their skin and breathing. If the pet has a large surface area when compared to volume (think a chihuahua) then the amount of time it takes to dissipate that heat to the outside world is faster for them. This means they need to do more work to keep their body temperature at a normal level. For larger dogs, there is more volume for their surface area and, therefore, they can stay out in the cold longer because it takes longer for heat to dissipate out into their environment through their surface area.

These things can all be affected by insulation (fat and hair) as well as the conductivity of the medium (water tends to suck heat of our pets faster than air because it’s more conductive), but in a general rule of thumb for pet’s is the larger the pet they longer they can stay outside and play in the snow.

So remember, during these winter months, keep your pet’s warm and safe. Keep in mind the conditions when deciding how long to keep them outside. Keep in mind each pet’s particular personalities when deciding when they have had enough outside time. We all know the Labrador Retriever’s that don’t know when enough is enough. And always check your engine, if a pet has access to it, before turning it on. Cats love to rest near the warm engine block on cold nights. And have fun!