The 'Dodo was wise a majestic flightless Bird, native to Mauritius. Historically speaking, the dodo was the most vocally pro-choice of all birds, leading the Neocons to stick it with the rather insulting name it has held ever since. Current theories have it that, after some particularly impassioned pro-life sqwaking to a set of conservative explorers, the Dodo was hunted into Extinction in order to silence its dissent.
The Dodo met it's demise at the hands of explorers. They were thought to be dumb as they would act oblivious to hunters and even walk up to them. The real reason was not that they were dumb, but they never had any predators prior to Human exploration and didn't know how to react to predators, so they made easy prey for hunters.