Why Do Dogs Love Bones? - We Save Dogs Life

Why Do Dogs Love Bones?

EVERYONE WHO HAS ever watched a dog chewing on a raw bone has probably noticed how blissful the experience seems to be for him. Even if the bone has very little meat on it and those few clinging meat scraps disappear quickly, the dog will continue to chew on the bone, scraping it or sometimes crushing it when he can get it far enough back into his mouth to work on with his molars. Ultimately, the dog will most likely eat most of the bone, and that is the scientific puzzle. Why would a dog, or any other carnivore, seem to want such an apparently non-nutritious food source to such a degree that it is willing to spend hours working on it, crushing and grinding it so that it can be consumed?
Oddly enough, we get our first inkling as to what’s going on here by looking at research on the diet of humans. John D. Speth of the University of Michigan excavated some sites in New Mexico that contained the bones of bison that had been killed around AD 1450. The strange thing about these deposits was that the ancient hunters had left most parts of the female bodies behind, yet they had dragged home as much of the male carcasses as they could carry. So what was wrong with these female bison? A clue comes from the season. While most known prehistoric bison kills happened in fall and winter, these animals were killed in the springtime. What makes female animals unappetizing during the spring turns out to be fat, or rather the lack of it. Pregnant and nursing cows are often severely stressed in the spring because they are carrying a nearly full-grown fetus or nursing a calf, and there is still a long time before there will be enough vegetation to use for adequate foraging. As a result they have to live off of their own fat reserves and their bodies become depleted of fat.
Similar fat depletion can occur when animals are near starvation during cold or dry seasons. At such times an animal’s body fat can drop to only a few percent of its total weight (far less than even the leanest cuts of beef). It may surprise many people to learn that a diet made up of almost pure protein actually contains too few calories for adequate nutrition and can even lead to protein poisoning. Apparently these hunters rejected the meat of the female bison because of its low fat content.
To see how inadequate a high-protein diet is in the absence of fat, we can look at a historical incident that occurred in Wyoming during the winter of 1857. A military officer named Randolph Marcy ran out of food and had to march his men all the way to Santa Fe, New Mexico, in order to find adequate provisions. His troops survived by eating their pack animals. Unfortunately, the poor quality of the meat nearly killed the men. Marcy reported, “We tried the meat of horse, colt, and mules, all of which were in a starved condition, and of course not very tender, juicy, and nutritious. We consumed the enormous amount of from five to six pounds of this meat per man daily, but continued to grow weak and thin, until, at the expiration of twelve days, we were able to perform but little labor, and were continually craving for fat meat.”
This brings us to the importance of bones in the evolution of carnivores. Seasonal changes swinging between warm and cold in the midlatitudes and wet and dry in the tropics affects the availability of the vegetable matter used as food by the animals that meat eaters depend on as their prey. The last reservoir of fat in an animal undergoing hard times is in the bones. Bone marrow is particularly rich, with more than half of its composition being fat. In addition, bonded to the calcium making up the bone itself is “bone grease,” which, although less digestible and concentrated, is still a substantial source of fat. If you are a predator and for some reason your prey is in very poor condition for part of the year, you will greatly increase the value of the meat you have if you can get some fat with it. The fat serves as a sort of nutritional multiplier. Therefore, the ability of carnivores to reach the bone marrow of their prey, and their desire to work at grinding down and consuming the bulk of a bone to access the bone grease, could mean the difference between life and death.
Some carnivores, like the hyena, have specialized teeth for crushing bones. Without these, our domestic dogs have to work harder, but they do have very strong jaws, and even a small dog can work up a bite strength of over two hundred pounds per square inch, which can gradually wear down the largest of bones. Most importantly, evolution has left dogs with the desire to work at getting this source of fat. Evolution uses the trick of making behaviors that are necessary for survival of the individual or species pleasurable (like eating or sex), so it has made the bone-chewing behavior of dogs a great satisfaction for them.
One caution: If you want to give your dog a bone, make sure it’s a raw bone. Cooking sweats out the bone grease and often melts away the fat in the bone marrow; furthermore, cooked bones are much more brittle, and eating sharp bone splinters can injure your dog.

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