Researchers in Japan and Spain found recently that Argentine ants, normally highly aggressive and territorial, are actually one huge global colony with three expanding centers: a 3,700-mile-long stretch in Europe, a 560-mile strip in California, and a swath of Japan's west coast. Researchers hypothesized the kinship because, when members from those groups were thrown together, they became docile.
A June article in the journal Emerging Infectious Diseases reported the worldwide reach of incidents of tapeworms that grow inside humans to nearly 40 feet in length. The most serious carrier, according to a Scientific American summary, is salmon sashimi. (Anthony Franz's 2008 lawsuit against a Chicago sushi restaurant, for a 9-foot-long tapeworm, is still pending.)