fossilized dodo bird
The dodo has been extinct since the mid-to-late 17th century. It is commonly used as the archetype of an extinct species because its extinction occurred during recorded human history, and was directly attributable to human activity.
The phrase "dead as a dodo" means undoubtedly and unquestionably dead, whilst the phrase "to go the way of the dodo" means to become extinct or obsolete, to fall out of common usage or practice, or to become a thing of the past.
From the Brighton Museum card:
B. DODO CASTS c1800
Willett collected natural history specimens throughout his life and was a long-serving member of the Brighton Museum (as distinct from the Fine Art) Committee. These pieces are plaster casts of the head and foot of one of the last Dodos from Mauritius in the Indian Ocean. These friendly, flightless birds, called duodo (stupid) by the Portuguese, were extinct by 1681.
Donated by Henry Willett, 1884