These studies show that living alongside humans can drive evolutionary change in wild and semi-domesticated species. Cats may still be changing—or perhaps cats have not changed much, and it is our relationship with them that has. In fact, some researchers suggest that cats first evolved to tolerate other cats living nearby before extending that tolerance to humans. Living alongside humans could still shape their behavior over many generations. We have changed what cats mean to us and, by doing so, changed the lives they now lead.