The dodo's classification was argued over for centuries. Sequencing of mitochondrial DNA from surviving material resolved it: Raphus cucullatus sits within Columbidae, and its closest known living relative is the Nicobar pigeon of South-East Asia. Its closest relative of all was the Rodrigues solitaire, another large flightless island columbid, also extinct.
The familiar image is unreliable too. Many seventeenth-century paintings appear to derive from overfed captive birds shipped to Europe, and skeletal analysis suggests the wild dodo was leaner and more upright than the barrel-shaped stereotype.
The cause of extinction is more nuanced than the popular story of sailors eating them. Accounts describe dodo meat as poor eating. Introduced rats, pigs, cats and macaques taking eggs and young from ground nests, together with habitat clearance, are generally treated as the dominant causes, with hunting a contributing rather than sole factor.