Here's what we know:
* Likely Introduction: Cats likely arrived with early human settlers, probably in the 16th or 17th centuries.
* Purpose: They were brought to control rodents and other pests associated with human settlements and ships.
* Impact: Unfortunately, cats became a major threat to the native wildlife, particularly birds and reptiles. They are a top predator on the islands, contributing to the decline of many endemic species.
So, while we can't give a definitive date, the most likely period for the introduction of cats to the Galapagos is during the initial colonization by humans.