(CNN) The Maya, a civilization that thrived in central America for almost two millennia, were skilled farmers, famed for developing highly technical irrigation systems, managing the tropical climate, and cultivating protein-heavy crops to feed their dense urban populations.
But they did not stop at squash, beans and maize. A new chemical analysis of animal bones found in a 3,000-year-old city in modern-day Guatemala provides the earliest picture yet of how the Mesoamerican civilization -- that stretched across Mexico, Guatemala and Belize and peaked between 250 and 900 AD -- bred and traded dogs, and may even have raised some for ceremonial purposes.
It suggests that the Maya in the city of Ceibal kept big cats in captivity, and not only ate dogs but also transported them long distances as early as 400 BC.
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"With Ancient Rome, Mesopotamia and China, we know that to build up their big civilizations they were moving animals around all the time, and it was part of their economic system," Ashley Sharpe, an archeologist at the Smithsonian Tropical Research Institute who led the research, tells CNN.
"What I was trying to do was see how the Maya were using the dogs, and see if it was similar to how other big civilizations were managing animals."
The study, published this week in the Proceedings of the National Academy of Sciences, analyzed the bones of a number of species found at Ceibal, including deer, opossums, turkeys, tapirs, wild cats and dogs. High levels of carbon and nitrogen isotopes were found in the bone collagen of the dogs, turkeys and one of the wild cats, suggesting they ate mostly maize, and were therefore fed by humans.
Almost all of the dogs at Ceibal were found to have died when they were about a year old. This is the typical slaughter age for most animals, and teamed with previous research indicating that the Maya ate dogs, it suggests a sophisticated system of meat management.
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The dog bones also indicate different breeds were present, and though Sharpe says the next step will be DNA analysis to determine how they looked, the current research confirms that breeds were used for different purposes. Some were eaten, whilst others were used as pets or for hunting.
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Elizabeth Graham, a professor of Mesoamerican Archeology at University College London, considers this one of the study's most significant discoveries: "that there are two kinds of dog," she says, "the dog that's your pet, that you hunt with, that has fur, and the dogs that were fed maize and were hairless -- the ones that were raised for food."
Sharpe says the study suggests that there was also a third, ceremonial purpose. Two of the dogs tested were found to be imported from the Guatemalan highlands, roughly 100 miles away. Unlike the local dogs, Sharpe says they were relatively old when they died, as their teeth were worn down and their bones had fused. They were buried in the city's ceremonial core, suggesting they might have been part of Mayan rituals.
The same goes for the bones of a large cat, most probably a jaguar, discovered in Ceibal. "It was fully grown, and from the isotopes it looks like it has eaten corn its whole life," says Sharpe. Since most wild cats do not eat corn naturally, it is likely it was being fed by humans, and therefore kept in captivity, she says. This assessment ties in with Mayan art, which often depicts kings holding jaguars or feline cubs.
Graham agrees there is little doubt the Maya used jaguars for ceremonial purposes, but she is skeptical of the suggestion that dogs were used in rituals. There is little record of dogs in a ceremonial context, she says, besides feasting.
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Graham's first thought was that dogs were transported to Ceibal from afar for breeding purposes -- because they required "a dog that was good for breeding fat dogs," she says, adding that the burial location may just have been circumstance.
"The rulers all wore jaguar skins, there were jaguar skins on thrones, but I don't think anybody used a dog skin," says Graham.