Island rodents take on nightmarish proportions. Duke Today, June 22, 2015. Duke University researchers have analyzed size data for rodents worldwide to distinguish the truly massive mice and giant gerbils from the regular-sized rodents. They found that the furry animals with chisel-like teeth are 17 times more likely to evolve to nightmarish proportions on islands than elsewhere. The results are in keeping with an idea called the “island rule,” which previous studies claimed didn’t apply to rodents. Picked up by the Daily Mail, the Charlotte Observer, BBC, and National Public Radio’s WUNC.