Table 1.

Comparative cellular composition of the brains of six rodent species

Species	Body mass, g	Brain mass, g	Total cells (×106)	Total neurons (×106)
Mouse	40.4 ± 11.6	0.416 ± 0.028	108.69 ± 16.25	70.89 ± 10.41
Hamster	168.1 ± 13.6	1.020 ± 0.147	166.12 ± 23.77	89.97 ± 9.55
Rat	315.1 ± 102.9	1.802 ± 0.313	331.65 ± 8.84	200.13 ± 12.17
Guinea pig	311.0 ± 49.1	3.759 ± 0.499	477.87 ± 10.57	239.62 ± 2.79
Agouti	2,843.3 ± 195.5	18.365 ± 2.061	1,941.46 ± 65.81	856.74
Capybara	47,500.0 ± 3,535.5	76.036 ± 3.787	4,866.44 ± 1,080.76	1,601.12 ± 81.16
Variation	1,176-fold	183-fold	45-fold	22-fold

Species are ordered by increasing brain size. Values are mean ± SD.