Figure 3.

Cellular scaling rules for afrotherian brains. Average brain mass for each species is plotted as a function of its total number of neurons (A) or other, non-neuronal cells in the brain (B). Brain does not include olfactory bulb. Afrotherian species shown in black, primates in red, scandentia in gray, glires in green, and eulipotyphlans in orange. Data from Herculano-Houzel et al. (2006, 2007, 2011); Azevedo et al. (2009); Sarko et al. (2009); Gabi et al. (2010). Power functions for each group are plotted. Exponents for brain mass × numbers of neurons are 1.451 ± 0.163 (afrotherians), 1.499 ± 0.107 (Glires), 1.016 ± 0.108 (eulipotyphlans), 1.130 ± 0.036 (primates with Scandentia). Exponents for brain mass × numbers of other cells are 1.025 ± 0.218 (afrotherians), 1.114 ± 0.049 (Glires), 1.105 ± 0.082 (eulipotyphlans), 1.040 ± 0.020 (primates with Scandentia).