There has been growing trend lately to attempt to classify dogs as omnivores, perpetuated mostly by kibble companies and sometimes even some veterinarians. Many pet owners who like to treat their pets as equals have readily accepted this, forgeting all about the essential needs of their pets, first as an animal species and then as a particular breed of that species. This anthropomorphisation of our pets has come at a very dear price indeed – their health, psychological wellbeing and ultimately their life.
Pets have become our psychological crutch and very often a surrogate for what is missing in human relationships. This dynamic has brought on grave misconceptions about canine psychology and canine nutrition. In other words, we are killing our best friends with ‘love’ and good intentions. Species specific diet is the concept which is completely lost in commercial pet food production.
Nobody thus far has managed to come up with a shred of convincing evidence to support the omnivore categorisation, a misconception which is slowly entering even some scientific books and university publications.
Left to their own devices, where they are readily and easily available dogs are shown to largely pursue a diet of small animals including rodents, birds, rabbits, insects, lizards and frogs, as well as smaller ungulates such as sheep, white tail deer and gazelle kids. [1,2,3] The rest of the time they spend scavenging carcasses and faeces. Some studies show that faeces can account for 20% of a dog’s diet.[3] The authors note that it is a symptom of their protein deficient diet. Indeed, many domestic dogs fed on highly processed food such as kibble will actively search for any faces in order to get nutrients they need.
Dogs seem to rely on several modes of feeding, they are very adaptive and so opportunistic that they are best described as scavenging carnivores rather than true hunters, [4] happily switching between pray when abundance makes it easy to do so. While they may not be the biggest, in areas where top predators have been removed, feral and free-roaming dogs are often top predators of many habitats. [5]
MATERIAL EVIDENCE
Even if we ignore behavioural studies of feral dogs or genetic evidence which suggests very close relation of domestic dogs with wolves we can easily conclude dogs are carnivores by closely examining their Digestive Anatomy and Physiology .
The most obvious answer to this ‘dilemma’ is staring at us straight from dogs’ mouth (to coin a mixed metaphor).
Although there is some variation in breeds, most adult dogs have forty-two teeth. Cats have 30 permanent teeth. The first thing you will notice upon opening a dog’s or a cat's mouth are big, impressive and sharp teeth. These canines, or fangs, are designed for grabbing, ripping, tearing, shredding and shearing meat. In addition to fangs, all carnivores – including dogs and cats – have so-called carnassial teeth, specially modified premolars whose only purpose is shearing flesh in a scissor-like way.
Dogs or cats are not equipped with large flat molars for grinding up plant matter. Their molars are pointed and situated in a scissors bite (along with the rest of their teeth) which powerfully disposes of meat, bone and hide. The top jaw has two molars on each side and the bottom jaw has three. These are the crushing teeth, used by wolves and wild dogs to crack medium-sized bones and in cats small bones of birds and rodents which are their natural pray.
Dogs’ jaw hinges open widely, allowing them to gulp large chunks of meat and bone. The skull and jaw design of a carnivore is deep and doesn’t allow much lateral movement of the jaw, which is necessary for chewing.
I emphasise ‘gulp’ because dogs do not chew; they are designed to bite, rip,shred,scissor/crush and swallow. If you observe your dog with a meaty bone you will realize s/he eats in the same manner as wolves do – by grabbing the meat with the carnassial premolars and ripping it off the bone.
Granted, wolves and wild canids will regularly forrage for some fruits ( mostly berries) and vegetables and if the hunt fails these foods can sustain them for limted periods of time but this still doesnt make them omnivores. Since vegetable sources ( never grains) make less then 25% of their diet we classify canids as facultative carnivores. Facultative means optional or not required. In other words their primary food is the meat or live prey but they are capable of surviving without it, perhaps not indefinitely.
Cats on the other hand are considered as obligate carnivores, this means they cannot survive without meat and their complete diet is live prey.
While dogs can detect sweet flavor and their taste buds respond to chemical called furaneol ( found in many fruits ) cats are virtually "taste blind" for this substance. It appears that dog's do like this flavor, and it probably evolved because in a natural environment dogs frequently supplement their diet of small animals with whatever fruits happen to be available.
Competition for meat in the wild is intense. Carnivores are designed to be able to gorge as quickly as possible. Dog owners are often shocked and worried by the way their dog gulps its food down. But this is part of the carnivore package; dogs are simply not hardwired for ‘table manners’ and no amount of conditioning them with regular meals will change this biological fact.
Many people new to raw feeding are afraid that their dog might swallow the meat and/or bones whole. Yes, they will pretty much do that. They will tear large chunks of meat off the bone, and then, if the bone is small enough (like a chicken or turkey bone), they will crush it by chomping down once or twice and then swallow.
Dogs’ stomach acids are much stronger than ours, which means they are capable of digesting large lumps of meat and even good-sized pieces of raw bone. The dog’s gut is highly acidic. During the digestion it can reach below pH 1.0. equivalent to car battery acid. No matter how much humans have influenced the appearance of dogs, they have done nothing to change the internal anatomy and physiology of their canine companions, who have a highly elastic stomach designed to hold large quantities of meat, bone, organs and hide. Their stomachs are simple; they have a relatively short foregut and a short, smooth, unsacculated colon, enabling food to pass through quickly. Vegetable and plant matter, however, need time to sit and ferment. [6, 7]
This requires longer, sacculated colons, larger and longer small intestines, and occasionally the presence of a caecum. Neither dogs nor cats have none of these. In fact, very often vegetable matter or grains come out of the dog or cat the same way they entered. This is why feeding vegetables and grains to obligate carnivores such as cats, or grains to factultative carnivores such as dogs is a very questionable practice, to say the least.
Even pre-processed grains can do very little good for your dog, and possibly cause a lot of harm. Dogs don’t normally produce the necessary enzymes in their saliva (like amylase, for example) to start the breakdown of carbohydrates and starches. This places the burden entirely on the pancreas, forcing it to produce large amounts of amylase to deal with the starch, cellulose, and carbohydrates in plant matter.
The carnivore’s pancreas also doesn’t secrete enzymes to split the cellulose into glucose molecules, nor have dogs become efficient at digesting, assimilating and utilising plant material as a source of high-quality protein. Only herbivores, and to some extent omnivores, are capable of this.
Commercial pet foods today consist mostly of wheat, barley and corn. In other words, they are full of complex carbohydrates which a dog or cat’s pancreas is simply unequipped to deal with. This is why pancreatitis and diabetes are two very common diseases in modern dogs and cats.
REFERENCES
- Scott, M. D. and Causey, K. (1973) Ecology of feral dogs in Alabama Journal of Wildlife Management, 37:253-265
- Boitani, L. and Ciucci, P. (1995) Comparative social ecology of feral dogs and wolves. Ethology Ecology and Evolution 7 (1): 49-72
- Butler J.R.A., du Troit, J. T., Bingham, J. (2004). Free ranging domestic dogs Canis familiaris as predators and prey in rural Zimbabwe: Threats of competition and disease to large wild carnivores, Biological Conservation 115: 369-378
- Macdonald, D. W. and Carr, G.M. (1995), Variation in dog society: between resource dispersion and social In: Serpel J, The domestic dog: its evolution, behaviour and interaction with people. Cambridge University Press; 1995. P. 199-216
- Prug, L.R., Stoner, C.J., Epps, C. W., Bean, W.T., Ripple, W.J., Laliberte, A.s. and Brashares, J.S. (2009). The rise of mesopredator, BioScience, 59: 779-791
- O’Reece, W. (2004) Dukes physiology of domestic animals (12th edition)Ithaca, NY: Comstock publishing
- Youngberg, C.a, Wlodyga, J., Schmaltz, S., Dressman, J.B. (1985), Radiotelemetric determination of gastrointestinal pH in four healthy beagles, American Journal of Veterinary Research, 46(7): 1516-1521
