Experts believe the fall in numbers is due to increased development as well as road traffic and pets. One hundred rock iguanas are killed by vehicles on Little Cayman each year, which amounts to 8% of the population, or the equivalent of 4,000 people being killed in traffic accidents per year on Grand Cayman, the National Trust explained. “This is especially troubling in light of the fact that Little Cayman is the smallest island with the lowest posted speed limits,†officials said.