Domestic cats have lived alongside human communities for thousands of years, hunting rats, mice, and other pests and serving as pets and a source of pelts and meat. Cats have received limited archaeological attention because their independence limits direct insight into human societies. An adult and juvenile cat recovered from the Emanuel Point wreck 2 (EP2) reflect what are, most likely, the earliest cats in what is now the United States. Zooarchaeological analyses of these and other archaeological cats in the Americas demonstrate that cats ranged substantially in size: some were comparable to modern house cats, and others were much smaller. Isotopic analyses of the adult cat from EP2 provides insight into early shipboard cat behavior and their diet, which appears to have focused on consumption of fish and possibly domestic meat. Cats accompanied sailors on ships where they were relied on to hunt rats and mice that were infesting ships’ holds. Interestingly, based on these isotopic results, the adult cat from EP2 does not seem to have relied heavily on rats as a source of food. These pests were unintentionally introduced to the New World, and cats would have followed, hunting both native and invasive pests.