For most of the roughly 15,000 years dogs have lived alongside humans, they ate whatever people gave them or whatever they could scavenge: table scraps, grain porridge, bones, organ meats, raw fish, and occasionally things like feces and hide. Commercial dog food didn’t appear until around 1860, and dry kibble as we know it wasn’t invented until 1956. That means for the vast majority of their history, dogs survived on a patchwork diet shaped by geography, their owner’s wealth, and sheer opportunity.
What the Earliest Dogs Ate
Archaeological evidence gives us a surprisingly detailed picture. Analysis of ancient dog feces from a Yup’ik site in Alaska revealed that dogs there ate multiple species of Pacific salmon (coho, chum, chinook, and sockeye), consuming not just muscle tissue but also bone, roe, and guts. Stable isotope studies from other Arctic coastal sites confirm that marine mammals and salmon made up the bulk of dog diets in ancient North American cultures. These dogs also ate animal parts considered unsuitable for human consumption, including hide.
This pattern of feeding dogs the leftovers, the scraps, and the parts people didn’t want appears everywhere in the archaeological record. Dogs were useful, but they ranked below humans at the table.
How Dogs Evolved to Eat Like Us
Living with humans changed dogs on a genetic level. Wolves are primarily carnivores, but as dogs began sharing human settlements and eating human food, they developed a dramatically improved ability to digest starch. The key change involves a gene called AMY2B, which produces an enzyme that breaks down starch into sugar. Dogs carry many more copies of this gene than wolves do, and those extra copies translate directly into better starch digestion.
This wasn’t a one-time event. Positive selection continued to increase starch-digesting ability in dog breeds that lived with agricultural populations eating grain-heavy diets. Breeds historically tied to farming cultures, like the Pekingese and Shar Pei, tend to carry more copies of this gene. Breeds from regions with seafood-rich, low-starch diets, like the Siberian Husky and Alaskan Malamute, carry fewer. In other words, dogs didn’t just passively eat what we ate. Over thousands of years, their biology reshaped itself around human cuisine.
Medieval and Early Modern Diets
By the medieval period, dogs were eating structured diets that varied enormously by social class, just like their owners. Hunting hounds kept by European nobility ate bran bread as their staple food, supplemented with meat from the chase. Kennels killed game specifically to feed the dogs even outside hunting season. Sick hounds received special diets of goat’s milk, bean broth, chopped meat, or buttered eggs.
Historical records from Lithuania spanning the 12th to 18th centuries provide even more detail. Elite hunting dogs ate oat porridge as their base food, supplemented with fat, blood, and meat waste. They also received lamb, pork, poultry, bread (sometimes baked specifically for the dogs), and salt. One 15th-century Polish nobleman, Jan Ostroróg, wrote that hunting dogs should eat only oats and never barley, because barley supposedly dulled their sense of smell. He recommended adding rye to help a thin dog gain weight and considered goat meat especially beneficial. During hunts, the dogs ate entrails and other waste from the killed game.
Stable isotope analysis confirms what the written records describe: cereals made up a huge portion of these dogs’ diets, contributing anywhere from 11% to 47% of protein depending on the site. Domestic livestock (cattle and pig) contributed another 22% to 40%. Wild game and fish made up smaller shares.
Urban dogs had it much worse. In early modern Vilnius and Kaunas, archaeological evidence suggests that feces consumption accounted for roughly 40% of urban dogs’ protein intake. City dogs were largely scavengers, eating bones, waste, and whatever they could find in the streets. Starvation and the consequences of this diet contributed to significant health problems.
Victorian Street Vendors and the Pet Meat Trade
As pet-keeping became more common in 19th-century cities, a small industry sprang up to meet the demand. In Victorian London, “cat’s meat men” pushed carts of cheap offal and horsemeat through residential streets, selling skewered chunks of meat for dogs and cats alike. A ha’penny bought a small snack; threepence got a more generous portion. These itinerant vendors were a fixture of urban life, and for many city dog owners, this cheap horsemeat was the primary way they fed their pets.
Outside the cities, the older patterns held. Farm dogs ate scraps from the kitchen and whatever they could catch. Working dogs on estates received a version of the medieval diet: grain-based porridge with meat or fat mixed in.
The Invention of Commercial Dog Food
The first mass-produced dog food came from an American businessman named James Spratt, who began manufacturing his “Meat Fibrine Dog Cake” in London around 1860. It was a baked biscuit made from blended wheat meal, vegetables, beetroot, and meat. Earlier versions of dog biscuits had appeared in England, combining vegetables, grain, and bran, but Spratt’s was the first to be marketed and sold at scale. It was aimed at English country gentlemen and their sporting dogs, not the average pet owner.
The next major shift came in 1922, when Ken-L Ration introduced the first widely popular canned dog food. Its main ingredient was horse meat, advertised as “lean, red meat” and carrying a U.S. Government Inspected label. Canned food quickly gained market share because it was convenient and dogs ate it readily.
How World War II Created Modern Kibble
Canned dog food dominated until World War II disrupted the supply chain. Tin was a critical war material, and canned dog food was not considered a good use of it. Several companies pivoted to dehydrated dog food, sold in boxes or cardboard containers and rehydrated with water or milk before serving. This wartime workaround pushed both manufacturers and consumers toward dry food formats.
The real breakthrough came in 1956, when Purina introduced Dog Chow, the first pet food made using pressure-processed extrusion technology. This process pushed a dough of ingredients through a machine at high temperature and pressure, creating the expanded, puffed kibble that’s still the standard today. The product was so popular that Purina couldn’t make enough of it and actually had to ration supply. By 1958, Purina Dog Chow was the nation’s leading dog food brand, sold through grocery stores rather than specialty shops. That grocery store distribution model made commercial dog food a mass-market product for the first time.
What Changed With Balanced Nutrition
Before commercial food was formulated to meet specific nutritional standards, dogs eating homemade or scavenged diets faced real risks of nutritional deficiencies or excesses. A dog eating mostly grain porridge might get enough calories but lack essential fatty acids or certain vitamins. A dog eating only raw meat could develop calcium imbalances. These problems weren’t always obvious. A dog could appear healthy while slowly developing deficiencies that shortened its life or weakened its bones.
The shift to commercially formulated food, developed with input from veterinary nutritionists, meant that for the first time in history, an average dog owner could provide a nutritionally complete diet without any specialized knowledge. That’s a remarkably recent development. For roughly 14,900 of the 15,000 years dogs have been domesticated, their diet depended entirely on what their human community ate, what it threw away, and what the dog could scrounge on its own.