Rapid evolution of prehistoric dogs from wolves by natural and sexual selection emerges from an agent-based model

Wolves are among the earliest animals to be domesticated. However, the mechanism by which ancient wolves were domesticated into modern dogs is unknown. Most of the prevailing domestication hypotheses posit that humans selectively bred wolves that were more docile. However, a competing hypothesis states that wolves that were less hostile towards humans would essentially domesticate themselves by naturally selecting for tamer wolves since that would allow for easier access to food from human settlements. A major critique of the latter hypothesis is whether evolution by this natural selective pathway could have occurred in a sufficiently short time span. Simulating the process would help demonstrate if such an objection is sufficient to dismiss this hypothesis. Thus, we constructed an agent-based model of the evolution of a single trait, a measure of human tolerance, in canines to test the merit of the time constraint objection. We tested scenarios both with and without mate preference to provide a potential sexual selective force. We used fecundity and mortality rates from the literature for validation. Hartigan's dip test of unimodality was used to measure if and when divergence of populations occurred. Our results indicate that the proto-domestication hypothesis cannot be rejected on the basis of time constraints.