Brain and Body Size Relations among Spotted Hyenas (Crocuta crocuta).

The relationship between brain size and body size across species "from mouse to elephant" is described by a function of positive slope. Almost uniformly, the relationship between brain size and body size within a species has a positive slope, though this is less steep than across species. The spotted hyena, Crocuta crocuta, differs from most other mammals in a number of ways including the fact that, on average, adult females weigh more than adult males and occasionally display greater body lengths.

Brain-body size relations in grasshopper mice.

Cranial volumes were measured on museum specimens of two species of grasshopper mice, Onychomys leucogaster brevicaudus and Onychomys torridus pulcher. These were compared with body weights and body lengths, as recorded on the museum tags. On average, females were heavier and slightly longer than males, but they had smaller cranial volumes by about 3%.