Heads up–Four Giraffa species have distinct cranial morphology

A giraffe’s forehead helps reveal which species it belongs to. The difference lies partly in the bony projection between the eyes, beyond the familiar paired structures on top of the head. Genetic research had supported four species, but the question remained whether their skulls also carried a consistent anatomical signature.

Nikolaos Kargopoulos, Jesús Marugán-Lobón and colleagues assembled 515 skulls from museum collections, African parks and reserves, and taxidermy collections. They made three-dimensional scans, marked corresponding points across each skull and compared shapes among groups. Because male giraffe heads grow larger and develop more prominent bony structures, the analyses also examined sex, growth and the influence of size on shape.

All four species differed statistically in cranial shape. The central forehead projection was particularly informative: it tended to be tall and pointed in northern males, lower and broader in reticulated males, smaller in Masai males, and faint or almost absent in southern males. Females showed subtler differences. Individuals still varied and overlapped, so these are not infallible visual identification rules. Instead, many small measurements revealed a repeated anatomical pattern: the genetic divisions have a counterpart in the shape of giraffes’ heads.