About 70 species of day geckos radiated from a common ancestor as they colonized small ecosystems across the Indian Ocean islands of and around Madagascar. On Rodrigues, 342 miles (550 km) northeast of Mauritius, the phenomenon of island gigantism occurred in this group at least twice, most spectacularly in the Rodrigues Giant Day Gecko. This lizard was as big as an arm and 18 inches (46 cm) long. Rats introduced by ships were likely responsible for its eradication, but it survived on a small satellite island west of Rodrigues until 1841. Phelsuma gigas is another product of evolution on Rodrigues that did not survive the evolution of man.