The term purring has been used liberally in literature, and it has been claimed that viverrids (civet, mongoose, genet), bears, badgers, hyaenas (et cetera) purr.
en.wikipedia.org The brown hyaena is a solitary and nocturnal carnivore that lives in clans and forages alone often over large distances.
theconversation.com In hyaenas, the reverse is true, and males exhibit more neuroticism than females, because they are consistently more high-strung and nervous.
en.wikipedia.org But if you smile too constantly, the smile is apt to get fixed like the smile of the hyaena sic.
blogs.telegraph.co.uk Recent research document excavations of a fossil bone bed, possibly resulting from the accumulation by hyaenas and redepostion by dongas (i.e., gullies).
en.wikipedia.org