Photo Credit: Waldemar Brandt from Pexels
Wolves, Dogs & PMR
By: Mia Lund
Wolves, Dogs and PMR
We often compare dogs (Canis Familiaris) with wolves (Canis lupus) as they are closely related and share a DNA which is very similar at 99.9%. Dogs and wolves can produce healthy offspring and all dogs are basically domesticated wolves. All modern dogs are descendants of wolves, though this domestication may have happened twice, producing groups of dogs descended from two unique common ancestors and dog breeds nowadays look very different in size and shape from wolves.
​
There are often claims made that because wolves are scavengers and they sometimes eat fruit and berries when prey is scarce, dogs should naturally need to eat fruit and berries as well. However this is starvation food for wolves and doesn’t provide any real nourishment.
​
If you take a look at wolf scat, most of it comes out the other end undigested as wolves’ and dogs’ digestive systems aren’t equipped to digest these things well. There are clearly a lot less calories in berries compared to meat and also nutrients that the wolves can’t metabolize very well. When the wolves have to eat berries to fill their bellies, they are losing a lot of weight.
​
Here is a photo from the Voyageurs Wolf Project ( VWP) , and it’s easy to see the undigested berries in the scat which shows that the wolves digestive system isn’t really well equipped to consume berries/vegetation… There is also evidence that wolves may scavenge fruit which is not very well digested either. Studies done on captive canids (e.g., red fox) eating fruit show that canids are likely losing weight when eating fruits because digestibility it not great.
​
Picture of Wolf Scat from Voyageurs Wolf Project
Photo Credit: Voyageurs Wolf Project
Wildlife Society Bulletin 1–3; 2020; DOI: 10.1002/wsb.1065
“Though wild berries do not provide as much caloric value as mammalian meat (0.51 kcal/g vs. 1.87 kcal/g respectively; Gable et al. 2017b) and are likely less digestible for wolves than mammalian meat, their abundance and relatively low risk and energetic cost to obtain likely makes berries a valuable alternate food source for wolves"
​
Similar findings have also been made in other studies:
Food habits of the wolf Canis lupus in Latvia based on stomach analyses
“Wild ungulates (cervids and the wild boar Sus scrofa) were the main food of the wolves (Table 1). Cervids were found in 64.7% of the samples, comprising 69.6% of the stomach content biomass, while wild boar were found in 25.9% of the samples, comprising 22.6% of the biomass. Inter alia, stomach analyses showed that roe deer constituted undoubtedly at least 41.5% of the biomass while unidentified cervids amounted to 28.1%. The abundance of roe deer and wild boar has increased considerably during the last decade (Fig. 1). Another significant food item was the beaver Castor fiber, which was found in 8.6% of the samples (6.4% of the biomass). Other food items found in wolf diet were small rodents, medium-sized and small carnivores (such as the fox Vulpes vulpes, the racoon-dog Nyctereutes procyonoides, and animals from the Mustelidae family), birds, domestic animals (a dog and a cat in this case), and plants and berries. However, none of these items exceeded 4.3% of the occurrence and 0.6% of the stomach content biomass”.
Estonian Journal of Ecology, 2009, 58, 2, 141ñ152
As you can see from the screenshots of this study the average amount of fruit and plant material found in wolves stomachs over all areas, ages and sexes is 4.3%, so very low. Look further and its slightly more in one area than another, slightly more in one sex than another, but most telling it’s all found in young wolves’ stomachs and none in adult wolves during winter. The study presumes this is due to younger wolves not yet being prolific hunters or allowed to eat as much of a kill if in a pack after actual puppyhood, so they supplement their diet with plant material in order to survive....
​
“The wolf is a carnivore, an animal suited for catching, killing and eating other creatures. Wolves prey primarily on large, hoofed mammals called ungulates. In Minnesota, the white-tailed deer is the wolf’s primary prey, with moose, beaver, snowshoe hare and other small mammals also being taken. Elsewhere, wolves prey on caribou, musk-oxen, bison, Dall sheep, elk, and mountain goats.
Wolves require at least 3.7 pounds of meat per day for minimum maintenance. Reproducing and growing wolves may need 2-3 times this much. It has been estimated that wolves consume around 10 pounds of meat per day, on average. However, wolves don’t actually eat everyday. Instead, they live a feast or famine lifestyle; they may go several days without a meal and then gorge on over 20 pounds of meat when a kill is made.”
​
Dr. L. David Mech is a wildlife research biologist who has studied large carnivores, especially wolves, and their prey. Here’s a link to his interesting wealth of articles which are worth a look for those interested.