Rats have plagued Hawaiians for a very long time, and not just the human residents.
Rats were the first invasive species in Hawaii. The first voyagers to the Hawaiian Islands brought Polynesian rats, Rattus exulans, and they spread quickly, colonizing the islands faster and farther than the people. Ancient Hawaii was a world full of spectacular birds, insects, and plants; the only native land mammal didn’t crawl – it flew – the hoary bat.
These native species evolved without seed-eating, egg-stealing rodents, so when rats arrived, plants were defenseless and birds were naive to this new threat. Compounding the situation, the Polynesian rat was followed by other rodents: the Norwegian ship rat and house mouse – hitchhikers in the European and American ships of the late 1700s and 1800s. Rodents ate their way through Hawaii, overrunning the islands from the shore to mountain top, fueled by a diet rich in plants, birds, snails and insects.
According to Peter Dunlevy, a U.S. Department of Agriculture Animal and Plant Health Inspection Service biologist with 15 years of experience researching rats, the greatest impact isn’t on any one particular area. Rats hammer numerous aspects of the environment – from the seeds they devour to the nesting albatross they attack. “But everything is on such a small scale with rodents; it’s easy to overlook.”
