Traditionally, when we discuss the history of dog foods, we look back, oh, about 150 years or so……tops.
The story typically begins with a guy named James Spratt (yes, that was actually his name). Around the year 1860, Spratt created a baked patty for dogs that contained a concoction of grains, beetroot, vegetables and beef by-products. They were sold as “Spratt’s Dog & Puppy Cakes.”
However, Spratt’s marketing skills were not so hot. Enter Carleton Ellis, an American inventor who is credited with the creation of margarine, varnish and paint remover, among other things. Ellis suggested that Spatt’s cakes and other foods of the time should be shaped in to small, dog bone-shaped biscuits. They were an instant hit.
The race between nutritional science and goofy marketing gimmicks in pets foods was on. To date, the marketers are clearly winning. (For more details and tidbits regarding the recent history of dog foods, see The Science Dog Courses, “Dog Food Smarts“).
Knowing this history, I was surprised and intrigued to find a recently published paper suggesting that Mr. Spratt may have been a bit late to the dog food cooking table (1). In fact, humans may have started preparing and feeding select foods to our dogs much (much) earlier.
This study was conducted by a team of archeologists who examined the remains of 27 adult dogs found in the Can Roqueta archaeological site near Barcelona, Spain. The dogs are estimated to have lived between 2500 and 3000 years ago and were buried in close proximity to human settlements. They were considered to be fully domesticated (although there is evidence of some interbreeding with wolves during that time), and appear to have had a variety of functions and roles in the communities.
Carbon & Nitrogen Dating
The researchers used carbon and nitrogen stable isotope dating to study the collagen make-up of the dogs’ bones. Because collagen is produced by an animal from dietary protein, this analysis provides several types of data about an individual’s diet. This information includes:
- The animal’s trophic level (i.e. place in the food chain….primary, secondary, tertiary or apex consumers).
- Whether the bulk of the animal’s food was coming from terrestrial (land) versus marine sources, plus the proportion of animal-source protein versus plant-source protein in the diet.
- The actual types of plants consumed based upon their patterns of photosynthetic activity, ability to fix nitrogen and classification as a domesticated cultivar versus wild plant (wow.)
Note: This type of isotope analysis is widely used and is an accepted approach for studying both human and dog diets from archeological sites.
Prior to this work, there has been ample evidence for early domesticated dogs consuming diets very similar to the human populations that they lived near or with. For example, in parts of Japan and coastal areas of North America, early dogs and their humans subsisted on diets almost exclusively comprised of marine animals and plants (go omega-3 fatty acids!). Conversely, early humans and dogs living in Mesoamerica consumed diets that contained a high proportion of maize (corn), while those existing in northern hunting communities subsisted on a highly carnivorous diet. What has not been clear in many of these ancient relationships has been whether or not the humans who were cohabitating with the dogs were intentionally preparing food for the dogs versus the dogs’ diets simply reflecting shared food scraps or scavenging.
The data collected by this group of researchers provides a bit of evidence that may help to answer this question.
- Some evidence of breed/type selection: Although many of the dogs were medium-sized, their morphological diversity suggested that humans were starting to select and possibly breed dogs for particular roles. Within the group, there were several unusually large dogs, suggesting early selection of dogs for pulling, guarding sheep and goats, or other forms of hard work.
- Varied diets: The isotope data for this group of dogs showed highly varied diets, with some dogs consuming a high proportion of plant-based proteins, while another set of dogs was fed a largely carnivorous diet very high in meat.
- Millet vs. meat: Further statistical analysis classified several general groups of dogs that lined up with ethnographic information regarding the cultures and agriculture/hunting activities of their associated humans. This diversity of the dogs’ diets apparently matched increasingly stratified human roles (and status), and suggested that dogs were being used (and fed) for different purposes.
- Different dogs, different foods: The researchers suggest that some of the dogs in the group were selected and used for work – herding or guarding sheep/goats or pulling loads. This subset of dogs was fed a diet high in cultivated grains to provide calories to support this work. In contrast another subset of dogs (the meat eaters) may have had enjoyed a very different role in society. These dogs were thought to be associated with the higher social status of their owners (the initial traders, possibly), were associated with funeral rituals and were buried alongside a (presumably, their) human. Thus these dogs were fed the more highly valued diet – one that was high in meat. (The very first pampered pets, perhaps?)
The differentiation of dogs’ functions and roles during the eras studied by these researchers (late Bronze and early Iron periods) along with varied diets potentially matching these different roles, suggest that the foods fed to the dogs during this period may have been intentionally prepared. The foods may reflect the needs of a working dog requiring high amounts of readily available calories (high grains) versus a diet fed to high status dogs associated with similarly high status humans. In both cases, this differentiation is suggestive of intentional preparation and feeding of a particular diet, rather than reflective of dogs consuming indiscriminately provided or scavenged human food scraps.
In other words, the people living near Can Roqueta with their dogs, more than 2500 years ago, may have been the first producers of dog foods. One has to wonder if their food came in bone-shaped biscuits….
Cited Paper: Albizuri S, Grandal-d’Anglade A, Maroto J, Oliva M, et al. Dogs that ate plants: Changes in the canine diet during the late Bronze Age and the First Iron Age in the Northeast Iberian Peninsula. Journal of World Prehistory, March 2021; doi.org/10.1007/s10963-021-09153-9.