Differences Between Pets and Wild Counterparts

Domesticated pets have evolved over millions of years and have diverged from their wild counterparts following domestication between 20,000 and 40,000 years ago. During the process of domestication, these animals have undergone considerable morphological, behavioral, and physiological changes that have adapted them to life alongside humans. Dogs, for example, have decreased aggression, increased tameness, and an ability to learn from humans compared to wolves [1]. While the behavioral and morphological differences are visually apparent, the physiological changes are often not and have a considerable impact on the nutritional needs of pets.

Differences between dogs and wolves

Unlike wolves who obtain their food from hunting other animals, dogs obtain food through humans. Pets receive their nutrition from their owners, and feral dogs have been shown to obtain food primarily through scavenging rather than hunting [2]. These changes in diet ultimately resulted in profound changes to the canine digestive system

Starch digestion

Starches and sugars are key energy sources in human and other omnivore diets. However, true carnivores generally lack the ability to digest starches since they are not a component of animal tissue. Recent research utilized whole genome sequencing to demonstrate that several genes related to starch digestion (AMY2B, MGAM, and SGLT1) were significantly upregulated in both mRNA expression and enzyme activity in dogs compared to wolves [3]. The genes AMY2B and MGAM are responsible for encoding the enzymes alpha-amylase and maltase-glucoamylase, which are involved in the process of starch digestion. The SGLT1 gene encodes sodium-glucose cotransporter 1, which is a brush border transport protein responsible for the majority of glucose uptake in the intestine [4]. These changes in the genetic code of dogs are likely responsible for the dog’s ability to utilize carbohydrate rich food sources such as corn or potatoes. However, it should be noted that dogs, like wolves, lack salivary amylase. Although salivary amylase does not contribute to a large portion of starch digestion due to the short retention time in the mouth, omnivorous species such as humans and pigs produce this enzyme.      

Brain structure and function

Despite having relatively similar head and brain sizes at birth, wolves grow to have substantially larger heads and brains [5]. Recent research has identified 19 regions in the dog genome thought to be affected by domestication that provide the code to synthesize nervous system proteins [3]. It is possible that during the process of domestication, selection for decreased aggressiveness, increased tameness, and other desired traits resulted in changes to the genome that ultimately drove the behavioral changes observed today.     

Similarities between dogs and wolves

Despite these and other differences, dogs and wolves do share some similarities as they evolved from a common ancestor. Although rare, dogs and wolves can breed to produce fertile offspring [6]. Wolves, like all carnivores, are adapted to periods of feast and famine. Following a large kill, wolves will consume a large amount of animal tissue, sometimes up to 22% of their body weight [7, 8]. This is generally followed by a period of low intake in which the body must rely on nutrient stores to meet metabolic requirements. Dogs have a similar ability to consume a large amount of food in a short period of time, with a stomach that can expand to accommodate large meals [7], followed by periods of fasting. In fact, one study reported a 117 day fast by an adult Scottish collie [9].

In addition to similarities in feeding patterns, dogs and wolves share similarities in vitamin A clearance. Vitamin A is transported as retinyl esters in the blood and cleared by the kidney, which reduces the risk of hypervitaminosis of vitamin A following the consumption of large amounts of liver from a recent kill [7]. 

Differences between domestic cats and wild cats

The domestic cat is a descendant of the African Wildcat, and it is generally accepted that cats have been domesticated over a much shorter period compared to dogs. Therefore, they retain more similarities to their wild counterparts compared to dogs. Domestic cats have several nutritional similarities to wild cats including a high dietary protein requirement, the inability to synthesize several amino acids, and the inability to synthesize retinol from carotenoids, among others [10]. Additionally, cats retain many of the same hunting techniques held by their wild counterparts [10, 11]. However, this is not to say that domestication has not imparted changes on pet cats. Aesthetic qualities strongly differentiate domestic cats from wild cats [12], and researchers have identified a mutation in the KIT gene that is responsible for white or white-spotted hair in domesticated cats [13]. While recent research has demonstrated that the domestic cat genome is more closely aligned with wild ancestors compared to dogs, there are distinct changes to genes associated with docility, memory, behavior, and the reward response [12]. It is likely that the selection of docile cats, along with them becoming more accustomed to humans for food drove these changes.

Summary

While domestic pets and their wild counterparts evolved from common ancestors, there are clear genetic, morphological, behavioral, and physiological differences that make them distinct species. These differences influence not only their nutritional requirements but their needs from an emotional and psychological perspective.          

Resources

 

1. Freedman, A.H., K.E. Lohmueller, and R.K. Wayne, Evolutionary history, selective sweeps, and deleterious variation in the dog. Annual Review of Ecology, Evolution, and Systematics, 2016. 47: p. 73-96.
2. Bradshaw, J.W., The evolutionary basis for the feeding behavior of domestic dogs (Canis familiaris) and cats (Felis catus). The Journal of nutrition, 2006. 136(7): p. 1927S-1931S.
3. Axelsson, E., A. Ratnakumar, M.-L. Arendt, K. Maqbool, M.T. Webster, M. Perloski, O. Liberg, J.M. Arnemo, Å. Hedhammar, and K. Lindblad-Toh, The genomic signature of dog domestication reveals adaptation to a starch-rich diet. Nature, 2013. 495(7441): p. 360-364.
4. Gorboulev, V., A. Schürmann, V. Vallon, H. Kipp, A. Jaschke, D. Klessen, A. Friedrich, S. Scherneck, T. Rieg, R. Cunard, M. Veyhl-Wichmann, A. Srinivasan, D. Balen, D. Breljak, R. Rexhepaj, H.E. Parker, F.M. Gribble, F. Reimann, F. Lang, S. Wiese, I. Sabolic, M. Sendtner, and H. Koepsell, Na+-d-glucose Cotransporter SGLT1 is Pivotal for Intestinal Glucose Absorption and Glucose-Dependent Incretin Secretion. Diabetes, 2011. 61(1): p. 187-196.
5. Coppinger, R. and L. Coppinger, Dogs: A startling new understanding of canine origin, behavior & evolution. 2001: Simon and Schuster.
6. Vilà, C. and R.K. Wayne, Hybridization between wolves and dogs. Conservation Biology, 1999. 13(1): p. 195-198.
7. Bosch, G., E.A. Hagen-Plantinga, and W.H. Hendriks, Dietary nutrient profiles of wild wolves: insights for optimal dog nutrition? British Journal of Nutrition, 2015. 113(S1): p. S40-S54.
8. Stahler, D.R., D.W. Smith, and D.S. Guernsey, Foraging and Feeding Ecology of the Gray Wolf (Canis lupus): Lessons from Yellowstone National Park, Wyoming, USA. The Journal of Nutrition, 2006. 136(7): p. 1923S-1926S.
9. Howe, P.E., H.A. Mattill, and P.B. Hawk, FASTING STUDIES: VI: DISTRIBUTION OF NITROGEN DURING A FAST OF ONE HUNDRED AND SEVENTEEN DAYS. Journal of Biological Chemistry, 1912. 11(2): p. 103-127.
10. Plantinga, E.A., G. Bosch, and W.H. Hendriks, Estimation of the dietary nutrient profile of free-roaming feral cats: possible implications for nutrition of domestic cats. British Journal of Nutrition, 2011. 106(S1): p. S35-S48.
11. Corbett, L.K., Feeding ecology and social organization of wildcats (Felis silvestris) and domestic cats (Felis catus) in Scotland. 1979, University of Aberdeen.
12. Montague, M.J., G. Li, B. Gandolfi, R. Khan, B.L. Aken, S.M.J. Searle, P. Minx, L.W. Hillier, D.C. Koboldt, B.W. Davis, C.A. Driscoll, C.S. Barr, K. Blackistone, J. Quilez, B. Lorente-Galdos, T. Marques-Bonet, C. Alkan, G.W.C. Thomas, M.W. Hahn, M. Menotti-Raymond, S.J. O’Brien, R.K. Wilson, L.A. Lyons, W.J. Murphy, and W.C. Warren, Comparative analysis of the domestic cat genome reveals genetic signatures underlying feline biology and domestication. Proceedings of the National Academy of Sciences, 2014. 111(48): p. 17230-17235.
13. David, V.A., M. Menotti-Raymond, A.C. Wallace, M. Roelke, J. Kehler, R. Leighty, E. Eizirik, S.S. Hannah, G. Nelson, A.A. Schäffer, C.J. Connelly, S.J. O’Brien, and D.K. Ryugo, Endogenous Retrovirus Insertion in the KIT Oncogene Determines White and White spotting in Domestic Cats. G3 Genes|Genomes|Genetics, 2014. 4(10): p. 1881-1891.

 

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About the Author

Dr. Chuck Zumbaugh works at BSM Partners as an Assistant Manager in Nutrition Services. He has experience in biochemistry, chemistry, software development, and animal nutrition. Outside of work, he enjoys spending time outdoors with his family in Kansas.