Dog evolutions, facial nerves and what dogs are ‘geared’ to eat
I would like to say that I am preaching to the converted that domestic dogs have every fibre of their being invested in catching and eating their meals. That ‘under the hood’ regardless of breed, they inherently desire to hunt and consume their prey. This as well as the nutritional benefits they gain from getting a meat boost in their modern diets.
Animal food sources are the most natural thing that dogs and their ancestors the grey wolves did to survive. Their society, their pack, their play was all based around this alpha predator top of the food chain motive. But there is still media debate about what is best for our dogs.
In this article we look at what happens when domestic dogs are allowed to roam in public. Will they laze around, play or hunt?
We also look at some very interesting research that suggests that the FOUR main dog Facial Nerves (Type A to Type D) respond to in food. The evidence overwhelmingly suggest that even facial nerves are designed for a meat eating existence!
But its easy to forget when people are drilled with kibble ads, that dogs might even have a glimpse of a primal memory about these sorts of things. It’s refreshing to read about science experiments highlighting this need.
AND why in a world obsessed with feeding humans LESS meat, that we should all be feeding our pet dogs MORE MEAT. Note single ingredient meat dog treats are an excellent way of supplementing ANY commercial dog diet.
The need for dogs to eat meat
The abstract for the research paper we are about to discuss looks at the innate feeding needs of domestic carnivores (dogs). It is a succinct and has a brilliant concept about why dogs might behave as they do.
“Domestic dogs (Canis familiaris) and cats (Felis catus) are the most abundant mammalian carnivores worldwide. Given that domestic carnivores rely on human-provided food, their densities are usually independent of prey densities. Nevertheless, underfed pets may need to hunt to meet their energetic and nutritional requirements. We explored the effects of different levels of care (provision of food) of dogs and cats on their predation rates on wild vertebrates in 2 areas of southern Chile. We interviewed cat and dog owners and analyzed prey remains in scats of pets to examine how domestic dogs and cats were managed and to gather information on the wild vertebrates killed and harassed by pets.” Ref 1
The magic of this experiment is several-fold. Many dog owners know how their cats love to knock a sparrow out of their apricot trees, but give little thought to how a wilder version of their domestic cat might survive in the wild.
There has been a LOT of discussion over the last decade about feral cats devastating native species animals in Australia. This is mostly why many councils restrict domestic cats to indoors living only – but what about dogs?
The reality is that most affluent countries don’t allow large packs of dogs to hunt for their own food, so this kind of experiment in somewhere like Australia would remain just a ‘thought experiment’. But results in Chile, where dogs are giving much more public freedom to do what is natural – really brings home what most modern breeds of dogs, even in Australia, would like to do, given the chance – that is HUNT for their food.
The Chilean results were fairly stunning …
“We used logistic regression to examine the association between pet care and the frequency of wild vertebrate remains in scats. The probability of a dog preying on vertebrates was higher for poorly fed than for adequately fed dogs (odds ratio = 3.7) and for poorly fed than for adequately fed cats (odds ratio = 4.7). Domestic dogs and cats preyed on most endemic and threatened mammals present in the study sites. Our results provide support for the hypothesis that the less care domestic animals receive from owners the higher the probability those animals will prey on wild vertebrates.” Ref 1
And here is where the ‘rubber hits the road’. The Chilean domestic dogs were 3.7 times more likely to hunt and kill their own food (ON TOP OF) what the owners fed, when they were “poorly fed”.
IN this case, and in Australia’s case, poorly fed doesn’t necessarily mean not fed enough, nor does it necessarily mean not fed a supposed aafco approved “balanced” diet.
The kibble and wet food that dogs consume from commercial companies is considered balanced when they follow the very low protein requirement of the American volunteer think tank affco’s 18% protein (FROM ANY SOURCE).
You might have read on social media that a lot of people think dogs eat grass because they are missing out on some kind of key ingredient in their diet. That might be true, but how could it be, if the vast majority of dogs are feed with aafco approved commercial dog food?
We and many raw feeders speculate that it’s the low amount of MEAT, and offal, and bio available protein – appropriate for dogs, that starves them of sufficient nutrition. If you can’t get your nutrition basics via commercial dog food, chances are if given the option, you would bother finding it yourself, in the wild (Chile style) – but most dogs in Australia don’t get that option.
DOGS can be “interpreted in terms of their descent from members of the order Carnivora. The dog is typical of its genus, Canis, in its relatively unspecialized dentition, and a taste system that is rather insensitive to salt. The preference of many dogs for large infrequent meals reflects the competitive feeding behaviour of its pack-hunting ancestor, the wolf Canis lupus.” Ref 1
“Unspecialized dentition” suggests that unlike a cats very sharp front teeth for ripping meat (that actually many dogs still have), that the dogs teeth set up isn’t definitive proof that they are still a carnivore. Kind of a strange side note in an experiment that proves that dogs have a strong desire to hunt and kill their own food (x 3.7) when given the chance!
The insensitive taste sense to salt for dogs is a carnivore trait so that they could eat a lot of meat. The taste buds that taste WATER – are also a specialised dog carnivore feature (to flush that extra salt.
Despite the continuing debate about dogs’ carnivore credentials (misinformation often sponsored by dog food companies wanting to go vegan for profit reasons) – most owners are aware of how much joy actual meat (raw, bones or dried dog treats) can give to a dog. It is primal, and it supplements commercial dog foods low bio available protein contents.
A domestic dog doesn’t need to stalk and pull down a full sized caribou, to prove that in its primal mind it still has an urge to hunt and consume meat – additional to its actual nutrition needs!
Your dog’s Feeding behaviour & food choice
One point FOR the carnivore aspect of dogs given by the authors is “Several breeds of dog have a reputation for being able to consume large meals very rapidly, and it is possible that this is the legacy of competitive feeding in the wolf.” Ref 1
“Rapid feeding may also be an adaptation to scavenging during the early stages of domestication. Dogs that retain this tendency can rapidly become obese if allowed to feed ad libitum.” Ref 1
Humans became agriculture specialists to avoid the vagaries of hunting and gathering lifestyles. Wolves used to do fine on their own, finding their own meat sources … but those that became domesticated ended up taking scraps from humans, not the best cuts of meat – and so the domestic dogs nutrition downfall began.
The authors go on to say “The taste systems of dogs and cats are based on what is probably a general carnivore pattern” ref 1
They also say “For most pet dogs, the selection of food provided by humans is based upon its appearance, odour, flavour, and texture.” Ref 1
But as we saw in a more recent article on dog food selection, ODOUR seems to be the primary sense dogs use .
We have also written articles specifically about the type, number and sensitivity of domestic dog taste buds – but the information below is a GREAT additional adjunct to what we know about dogs, and is based upon FACIAL NERVES in dogs!
“Among the taste buds of the facial nerve in dogs, the most common units (Type A) respond primarily to amino acids, many of which, such as L-proline and L-cysteine, are described as “sweetish” in humans); these units also respond to mono- and disaccharides.” Ref 1
“amino acids” are the building blocks of PROTEIN. There are TWENTY amino acids in every protein. Of which NINE are ESSENTIAL AMINO acids – these need to be supplied directly by proteins in food, because the dogs insides can’t manufacture them (unlike the other 11 that they can recombine other chemicals to make).
If the MOST COMMON Type A facial nerves in dogs respond to amino acids – this means that they NEED these amino acids MOST.
There are three types of food classes: Protein (amino acids), Carbs (sugars), fats. Most vegetables and grains are low in protein (or bio available proteins) and relatively high in Carbs. Most meats are HIGH in bio available Proteins and have NO carbs.
This suggests if a dog has the bare minimum or even greater than the bare minimum protein, but from the wrong (high amount of vegetable sources) – then they are going to have a deficit. No wonder that Chile dogs like to find their own protein sources in prey.
“Type B (FACIAL NERVE) units, which are different from those found in rats, respond to carboxylic acids, phosphoric acids, nucleotide triphosphates, histidine, and other Brønsted acids. “
Omega-3 carboxylic acids are derived from fish oil [docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)].
“Usually feed ingredients from animal origin are higher in total nucleotides whereas plant derived raw material are lower.”
L-histidine (HIS) is an essential amino acid – typically found at high levels in animal meat.
“Type C [FACIAL nerve] units respond primarily to nucleotides that are associated with the “umami” taste in humans.” Ref 1
While tomatoes. Mushroom and seaweed have Unami taste, Unami is mostly associated with MEATS. In particular pork, beef, fish, and shellfish. In fact the fact that dogs have a taste ability to sense and ENJOY the Unami taste simply suggests more evidence of their meat eater credentials.
Type D, [dog facial nerves] … respond to a small number of “fruity-sweet” compounds, such as furaneol .. It was suggested that broad links can be drawn between these specializations and carnivory because many of the compounds mentioned occur in raw flesh and in carrion … but it is still unclear how the information from the taste buds is integrated into the brain or translated into feeding behaviour. [food] Odour must also play a major role in food selection because anosmic dogs (no sense of smell) show a reduced discrimination between different types of meat.” Ref 1
CONCLUSIONS
While the science paper we reviewed aimed to explore the evolutionary basis for feeding behaviour of your domestic dog … it didn’t take a clear position on whether dogs should be considered full carnivores.
A full carnivore is an animal like a domestic cat, called an obligate carnivore. The very fact that early domesticated dogs still have to scavenge for scraps because early owners were not flush with meat – meant that their systems had to somewhat adapt (not become sick) from eating carbs.
The modern-day Chile dog experiments showed that when given the option to laze at home, or hunt for their own food, dogs that were not well fed (or dogs fed on non-meat food) – were 3.7 times more likely to hunt and kill their own food, than dogs that were given enough of the right protein sources.
Rather than disprove the highly desired carnivore food the authors exploration of what a dog’s facial nerves (types A to D) mostly respond to seemed to point extremely strongly to another basis for dogs desiring and needing mainly animal (meat) products.
Commercial dog food typically has well below 50% meat and offal products in them. Because they are pulverized, you don’t see what you are getting.
Most dog owners visiting our site are at least open to the possibility that their dogs might need more meat in their diet. It seems the more we explore these open-ended science papers, the more reasons we find that confirm dogs are the closest things to being obligate carnivores, except the specific “obligate” classification.
Reference
REF 1 Influence of care of domestic carnivores on their predation on vertebrates
Eduardo A Silva-Rodríguez 1, Kathryn E Sieving pub 2011 Jun 9.