This is Scientific American 62nd Science.

I'm Cynthia Graber.

As humans developed civilizations in Eurasia and Northern Africa,

they also domesticated animals for food and labor,

horses, cows, goats, pigs, sheep, and a few others.

But no evidence existed for the deliberate cultivation

and breeding of animals in North or Central America

until now.

So at this ancient city of Teo Tewa Khan in particular,

which is really one of the earliest urban cities

in North America.

Andrew Somerville of the University of California,

San Diego, talking about the metropolis that once

existed some 30 miles northeast of present-day Mexico City.

Previous excavations have found a lot of rabbits, but at one compound in particular, they found more evidence that they were interacting

with rabbits more intensively. There was a statue of a rabbit. There was evidence that maybe they were butchering them.

And this compound, which is called Ostoyo,

Wulco, actually had almost twice as many rabbit bones

relative to the other complexes at the city.

So it did seem like something was different with this particular compound.

Somerville and colleagues tested 134 rabbit bones at the 2,000-year-old site, as well as 13 contemporary samples.

If the ancient rabbits fed on wild vegetation, the carbon isotopes in the bones would show evidence

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