Were Bronze Age dogs vegetarians? Proteins in 3,000-year-old bones reveal canines in mostly grains

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A dog with a bone is the personification of happiness, but early domesticated canines ate almost no meat, according to a new study.

Researchers examining proteins in the bones of Bronze Age dogs in Spain found that many were fed a diet consisting mainly of grains, such as millet.

That menu may have been a necessity, as their human companions themselves were low on meat – but it offered a clear advantage.

Dogs were often put to work to herd livestock or protect the farm, and a high-carb diet provided them with the energy for their demanding work.

Researchers examining proteins in the bones of Bronze Age dogs in Spain found that many were fed a diet consisting mainly of grains, such as millet.

Researchers examining proteins in the bones of Bronze Age dogs in Spain found that many were fed a diet consisting mainly of grains, such as millet.

When dogs were first domesticated is a topic of great scientific debate, with some experts setting the date as 14,000 years ago and others even going back as far as 40,000 years.

Many evolutionary scientists believe it started in Eurasia, when a population of wolves on the edge of a Stone Age hunter-gatherer camp began to feed on scraps.

At that time they almost exclusively ate meat, but the rise of agriculture caused a major shift.

“When human societies began to domesticate plants during the Neolithic, hunting declined and the human diet was mainly based on vegetables,” said Silvia Albizuri, a zoo archaeologist at the University of Barcelona. New scientist

That menu may have been a necessity, as their human companions themselves were low on meat - but it offered a distinct advantage.  Dogs were often put to work to herd livestock or protect the farm, and a high-carbohydrate diet ensured they had the energy for their demanding work

That menu may have been a necessity, as their human companions themselves were low on meat - but it offered a clear advantage.  Dogs were often put to work to herd livestock or protect the farm, and a high-carbohydrate diet ensured they had the energy for their demanding work

That menu may have been a necessity, as their human companions themselves were low on meat – but it offered a distinct advantage. Dogs were often put to work to herd livestock or protect the farm, and a high-carbohydrate diet ensured they had the energy for their demanding work

“Dogs began to be fed plants, mainly grains,” Albizuri said.

Albizuri and her colleagues studied the remains of 36 dogs found in Can Roqueta, an archaeological site about 25 miles north of Barcelona that was first inhabited in the Stone Age.

The canines lived in the area between 1300 and 550 BC, during the Bronze Age and Iron Age.

WHEN WERE DOGS INLAND FOR THE FIRST TIME?

A genetic analysis of the world’s oldest known dog remains suggests that canines were domesticated by humans who lived in Eurasia between 20,000 and 40,000 years ago.

“The process of domesticating dogs would have been a very complex one, involving several generations with distinctive canine traits gradually evolving,” Krishna Veeramah, a professor of evolutionary science at Stony Brook University, told MailOnline.

“The current hypothesis is that the domestication of dogs probably originated passively, with a population of wolves somewhere in the world living on the outskirts of hunter-gatherer camps feeding on garbage made by the humans.”

Wolves that were less aggressive would have been more successful in this strategy, Veeramah said.

Ultimately, they would have developed a mutually beneficial relationship with humans, ‘evolving into the dogs we see today’.

They were buried in pits, suggesting they were cared for by humans.

The scientists studied the carbon and nitrogen levels in the dogs’ bones, which can indicate what an animal was eating.

Ten of the dogs were omnivorous and nine were on a high-meat diet, according to a new study published in the Journal of World Prehistory.

But the remaining 17 showed almost no signs of eating animal flesh – some had carbon and nitrogen levels barely distinguishable from the livestock they guarded, New Scientist said.

For generations, a vegetarian diet would have meant that dogs developed jaws that are weaker than their wolf ancestors, and smaller, flatter teeth that could chew on plants and grains better.

But the shift wasn’t universal: In colder climates, where hunter-gatherer societies persisted, dogs would still live on meat, Albizuri said.

“In today’s dog breeds, there are significant genetic differences related to starch metabolism,” she added.

With the growing popularity of a plant-based diet among humans, more modern pet owners have also put their dogs on a diet.

A 2020 UK survey found that one in 20 cats and one in five dogs is fed an exclusively vegan or vegetarian diet from their owners.

But experts say well-meaning owners can put their four-legged friends at risk.

“If your personal belief means that you don’t want to eat animal protein, that’s fine, but that diet is not designed to meet your pet’s welfare standards,” said Daniella Dos Santos, president of the British Veterinary Association. BBC

Cats are obligate carnivores and need nutrients found only in animal meat – they can absorb small amounts of plant matter but lack the physiology to digest it completely.

Dogs are slightly better adapted to diets with less meat and more vegetable starch, as they evolved as our companions by taking all the leftovers offered by prehistoric humans.

Unlike cats, canines have amylase genes that allow them to digest and extract nutrients from plant material.

“It is theoretically possible to feed a dog a vegetarian diet, but it is much easier to get it wrong than it is to get it right,” Dos Santos told the BBC.

“You should do it under the supervision of a veterinary nutritionist.”