Read this: Tuberculosis has been present in humans since antiquity. The earliest unambiguous detection of M. tuberculosis involves evidence of the disease in the remains of bison in Wyoming dated to around 17,000 years ago. However, whether tuberculosis originated in bovines, then was transferred to humans, or whether it diverged from a common ancestor, is currently unclear. A comparison of the genes of M. tuberculosis complex (MTBC) in humans to MTBC in animals suggests humans did not acquire MTBC from animals during animal domestication, as was previously believed. Both strains of the tuberculosis bacteria share a common ancestor, which could have infected humans as early as the Neolithic Revolution.
Now answer this question, if there is an answer (If it cannot be answered, return "unanswerable"): What did animals get TB from?
unanswerable