New CT scans of two of the only known complete dodo skulls indicate the extinct bird had an unusually keen sense of smell and dusk-adapted vision, complicating its centuries-old reputation as a slow-witted animal that made itself easy prey for sailors.
The study, led by University of Lethbridge researchers Sara Citron and Andrew Iwaniuk with collaborators from Flinders University and the Natural History Museum of Denmark, was published Aug. 5 in the Zoological Journal of the Linnean Society. The team compared internal skull scans of the dodo and its close relative, the Rodrigues solitaire, against 36 living pigeon and dove species, digitally reconstructing the cavity once occupied by each bird's brain, according to Sci.News.
"The dodo is one of the world's most recognizable extinct animals, yet surprisingly little is known about how it actually lived."
— Peter Andrew Hosner, Natural History Museum Denmark
The scans showed the dodo's olfactory bulbs — the brain structures that process smell — made up about 3.4% of total brain volume in one intact specimen, notably larger than in typical pigeons, suggesting the bird relied heavily on scent to locate fruit and nesting sites on Mauritius. Its optic lobes, by contrast, were more than three times smaller relative to brain size than those of the Nicobar pigeon, a pattern researchers associate with activity around dawn and dusk rather than full daylight, per ScienceDaily.
Crucially, the team found no evidence the dodo's cognitive brain regions were undersized relative to its body — undercutting the popular caricature, cemented by the "dumb as a dodo" idiom, that the bird's tameness around humans and rats reflected low intelligence rather than simply no evolutionary experience with predators. That reputation dates largely to European sailors' accounts of a flightless bird with no fear of humans, an image later reinforced by crude illustrations and the dodo's role as a symbol of extinction in popular culture.
Only two complete dodo skulls are known to survive, held in collections in Copenhagen and Oxford, making high-resolution scanning of either specimen rare. Researchers say the findings reopen questions about how the dodo foraged and bred before it was wiped out within a century of Dutch sailors' arrival on Mauritius in the late 1500s, and they plan further comparisons with other extinct island birds.