Researchers believe the Aztec burial site dates back to between 1350 and 1520, a time when mass dog burials was not a common practice, the Examiner reported.
During this time, dogs were often buried with people because they were believed to have powers to help guide the dead to their new life after death.
Dogs were buried on the grounds of pyramids and other structures of significance to the Aztec culture.
Twelve medium-size dogs were found buried at the site in a strategic pattern.
Researchers plan to conduct tests to determine the breed of dogs and how they died, perhaps to help reveal why they were buried in such a way.