Lemurs in fancy hats are helping researchers better understand how extinct creatures moved. Although “fancy” may not be the best word for the attire (sadly, we’re not talking about fedoras or bowlers here). As part of a new PNAS study, researcher Michael Malinzak and colleagues fitted lemurs, lorises, and galagos of the Duke Lemur Center with special caps that tracked how the primates moved their heads as they walked, hopped, and clambered around.

The reason for the high-tech fashion was to gauge the relationship between head movements and the anatomy of the primates’ inner ears. From fossil humans to dinosaurs, researchers have often reconstructed the kind of head movements prehistoric animals were capable of by looking at the anatomy of semicircular