Summer is nearly here in North America, so what better time to talk about cold feet?
If you’re game for an experiment, turn on the radio to your favorite music station. Next, fill a bowl with ice water. Now slather shortening around the index finger of one hand. Put it on thick, and don’t forget to cover the tip of the finger. Ready? When a song on the radio starts to play, stick the index fingers of both hands into the ice water, and keep them there until the song is over, usually about two minutes (note: if the radio starts to play Procol Harum’s “In Held ‘Twas in I,” wait for the next song. “In Held ‘Twas in I” is over 17 minutes long).
The point of the exercise is for you to understand the insulating properties of blubber which you experienced when it took longer for the finger covered in shortening to get cold than it did for the “naked” finger.
The pads on a dog’s paws have a thick layer of fatty tissue that insulates the inner foot tissues from extreme temperatures, so it doesn’t conduct cold as rapidly. What makes a dog’s foot so interesting is that as the paw gets cold when it steps in the snow or frozen ground, arteries transfer the chilled blood back to the body where it warms up again. This was learned when Japanese researchers used electron microscopes to look at the paws of domestic dogs. What they found was a circulatory adaptation unlike other animals. Dogs can transfer heat from the artery to a network of veins in the area so that colder blood is unable to return to the body. The heart is able to pump warm blood to the feet fast by utilizing the artery closest to the neighboring veins in the footpads. This system, dubbed the “counter-current heat exchanger,” also limits the amount of blood near the body’s cool skin.Coupled with a high amount of freeze-resistant connective tissue and fat (remember the blubber) located in the pads of the paw, and a dog’s paws stay warm. All of the aforementioned is why scientists now think that domestic dogs first evolved in cold environments before spreading out into other climates. Dog nerds will want to read the technical paper on the subject, “Functional anatomy of the footpad vasculature of dogs: scanning electron microscopy of vascular corrosion casts.
There are still reasons to put booties on a dog, particularly working dogs, and those competing or playing in the snow for longer periods of time. Rough ground, toxic covered surfaces, and the potential to step on sharp objects are also causes for booties. Read this review of the top rated booties, as well as this one. Be aware, too, of Musher’s Secret, originally developed for sled dogs. It’s a non-toxic natural wax that rubs right onto the pads of a dog’s feet to create a barrier from harsh conditions.
Our image of the Teddy in boots comes, “How to Train Your Dog to Wear Boots.”