The dodo is an extinct species of flightless bird formerly found on the island of Mauritius in the Indian Ocean in the 1600's. Extinction occurred due to the destruction of habitat and the introduction of non-indigenous animals such as cats and rats. Once the dodo bird became extinct, the major noted effect was the inability of the calvaria tree to germinate seeds. Some scientists speculated that this was due to the fact that dodo birds had not eaten and digested the seeds. The relationship between the dodo bird and the calvaria tree is an example of animal-plant mutualism but this theory has been challenged. There is no documented evidence regarding the effect the dodo birds' extinction had on other species of animals on the island but if one were to analyze a typical food web, any competing species that occupied the same niche would have been impacted. Species that ate fruits, nuts, and seeds would have had more resources so their populations may have increased depending on the effects of the non-indigenous species of course.