This is Part 3 of a 3-part series. If you haven’t yet read Part 1: Wolf’s Profound Gift to Humankind and Part 2: If We Were Carnivores... I invite you to do that first.
In the two previous posts we explored the role Wolf played in our transition from a largely plant-based diet to one that is meat-based. A reader responded with this comment:
“I appreciate this theory on evolution and diet of hominids. Vegans like to claim we are naturally herbivores or vegetarian-based on our morphology—particularly teeth and hands and long guts that resemble other herbivores. But the acidity in our guts resembles carnivores more. Digesting a 20-banana smoothie just doesn’t feel natural (speaking from experience). Seeing this as an evolution from herbivore primates toward carnivores (but respecting our known history as omnivores) with some herbivore features and some carnivore features makes sense to me—we are evolving toward carnivores but not completely there yet. As does evolving with Wolf. Actually, I can see the rekindling of our relationship with Wolf as leading to our rekindling of relationship with all of Nature as well. Especially as Wolf is solving many of the wildlife problems that we created, where we leave him/her be.”
The reader brought up some good points that beg further exploration. Let’s begin by looking at the similarities and differences in the Wolf and Human digestive systems. But first, I encourage those of you who haven’t read the previous two posts to do so, as the following will then make more sense.
Both Wolf and Human digestive systems are highly efficient, with Wolves being able to extract up to 90% of the energy from what they eat, and Humans clocking in at up to 95%. Where Wolves can consume 20% of their body weight in one meal, Humans are capable of only 3 to 5%. Here is where the differences in digestion start to show—not in terms of what is consumed, but in how it is consumed and processed
Let’s take a look at the digestive system itself. Large wolves have digestive tracts around 8 feet in length, and large humans have up to 30-foot-long digestive tracts. The radical difference is based on two different evolutionary tracks. Wolves, being apex predators, have to kill and eat fast, due to the highly mobile capabilities of their prey and the competition from other predators for their kills. Humans, on the other hand, can eat in a more relaxed manner when they function as scavengers, and when they consume food they have previously stored.
Humans, then, have the luxury of eating more often, and in lesser amounts, than Wolves. A Wolf consumes up to 20 pounds of meat at a time, which leaves her wanting to do nothing more than lay around for a few hours and let the food digest. Humans, on the other hand, have no trouble with mobility after their relatively smaller meals.
What we have just covered points to the anatomical differences in each species’ digestive system. Starting with the teeth, Wolves have four types: canines, incisors, premolars, and molars. The large, elongated canines are used to grasp and take down prey: the incisors, which lie between the canines, are effective at stripping the bones of meat; the premolars, which rest behind the canines, act as knives, to quickly slice off large chunks of meat, which get immediately swallowed; the molars have the strength to crush nearly all bone, which gets swallowed and digested for its mineral content, and the fat-rich marrow gets consumed as well.
Humans, on the other hand, have no need for highly developed canines, as either Wolves do the killing for them or they use “canine” projectiles in the form of spears and arrows. Neither do Humans need slicing premolars, as they have adapted their opposable-thumb grips to the use of slicing tools. The same is true with molars, as stones work very well for cracking bone.
Now let’s take a look at the digestive process itself. Rather than chewing food, Wolves have an enzyme-rich saliva which begins to break the food down immediately. For at least 400,000 years, which is when the Homo sapiens lineage diverged from other hominids, Humans had fire to help them break down foods and thus make them more easily digestible.
All of the above explains why it takes only 8 hours on average for food to pass through a Wolf’s digestive system, and it takes 24 to 72 hours for Humans. Wolves need fast energy and quick elimination in order to remain mobile and keep up with the herds. Humans, on the other hand, can take their time to process, chew, digest, and eliminate their food, and they can eat more regularly than Wolves, which gives them a consistent energy source and no need to bog themselves down with a large consumption of food, as Wolves do.
Chewing is a critical factor in Human digestion, and it is perhaps the most glaring difference between the way they and Wolves consume food. In the Human brain stem is a region called the swallowing center, which triggers the swallowing reflex when food in the mouth is broken down enough for easy digestion. When Humans try to swallow food before it is adequately broken down, it can trigger the gag reflex, which brings the food right back up for more chewing. Wolves have a much more relaxed gag reflex, which allows them to swallow large chunks of meat quickly and easily.
In a previous post, we talked about the convergent evolution of Wolves and Humans. The digestion story is another beautiful example, where two distinctly different species are consuming the same food, in similar circumstances. Yet they evolved quite dissimilar digestive processes, and still achieved the same results in terms of digestive efficiency and the ability to coexist, often to the mutual benefit of each species.