The Elephant bird, now extinct, once lived on the island of Madagascar. Standing tall at 10 feet it weighed about a ton! And needless to say, it was flightless. Reasons of extinction have not yet been ascertained by it is generally believed that the elephant bird’s extinction resulted from human activity, perhaps not surprising when one of their giant eggs would have fed an entire family (Source: BBC). The link also has a nice video which shows Sir David Attenborough solving a jigsaw puzzle and piecing together the egg fragments.