Experts disagree on when the island's Polynesian inhabitants first reached the island. Some believe that they arrived around 800 CE, though a 2007 study found the time to be 1200 CE. The inhabitants created a thriving and industrious culture, as evidenced by the island's numerous enormous stone "moai" and other artifacts. However, land clearing for cultivation and the introduction of the Polynesian rat led to gradual deforestation. By the time of European arrival in 1722, the island's population was estimated to be 2,000 to 3,000. European diseases, Peruvian slave raiding expeditions in the 1860s, and emigration to other islands such as Tahiti further depleted the population, reducing it to a low of 111 native inhabitants in 1877.