Figure 3.

Evolution of the sensory ecology of elephant birds and other palaeognaths showing transitions in daily activity patterns (inferred from reconstructions of ancestral relative optic lobe size) and foraging habitat (inferred from reconstructions of ancestral relative olfactory bulb size). Diurnal activity patterns were ancestral for palaeognaths, followed by transition to crepuscularity independently in elephant birds/kiwi, in cassowaries and possibly in some moa. Within the elephant bird–kiwi clade, nocturnality arose independently in the largest elephant birds (Aepyornis) and in kiwi. Open habitat (e.g. grass- and shrubland) was likely ancestral for palaeognaths, followed by transition to forested habitat in the clade including elephant birds, kiwi, cassowaries and emus. Emus likely subsequently transitioned back to open habitat as Australia became deforested leading up to the present. Forested habitat was likely ancestral for tinamous followed by transition back to open habitat in the clade containing the Chilean and red-winged tinamous. Although the heavy-footed moa likely occupied open habitat, other moa taxa occupied forested habitat and it is unclear if open or forested habitat was ancestral for moa. Optic lobe size ancestral state reconstruction (upper tree) is based on electronic supplementary material, figure S7. Olfactory bulb size ancestral state reconstruction (lower tree) is based on electronic supplementary material, figure S5.