Figure 5.

Graphical presentation of the progression of different mammal groups through the 12 stages of vestibular apparatus development (see Table1 for details). The stages for individual animals have been plotted against body length in mm on a logarithmic scale for monotremes (A), dasyurids, didelphids and peramelids (B), three types of diprotodontids (C – the phalangerid Trichosurus vulpecula; D – koala/common wombat and macropods); rodents and humans (E). Vertical grey bars show the body length at which birth or hatching occurs for each relevant group, except humans, which are born at a body size beyond the abscissa of graph E.