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Description

A selection of extinct members of the carnivoran hyaenids, to scale.

A common cultural stereotype of hyaenas is that they are greedy, stupid, cowardly and ugly. This isn't just a Western viewpoint; some stories stem from native African folklore, but it differs greatly between ethnic groups. Scavenging and robbing graves certainly doesn't tend to bestow a good name! But the reputation is misplaced as hyaenids include active apex predators, complicated clan dynamics, perform co-operative problem-solving, include secretive insect-eaters and most famously species which can crack open bones to access the marrow. Today just four species constitute the entire hyaenid family (one of the smallest mammalian families), however there is extensive fossil record with widespread diversity across over 100 named species.

Bone-cracking is a relatively recent development in hyaenids. The earliest forms from the Early Miocene originated in Europe and were insect/small veretbrate hunters. Species like Protictherium and Plioviverrops were more like civets or mongooses, even capable of climbing trees. During the Miocene, hyaenids split into two main niches: the agile dog-like forms and the heavier bone-crackers. The dog-like hyaenids, such as Hyaenotherium were very successful during the Miocene but showed a massive decline prior to the Pliocene, as canids migrated west across the land bridge of Beringia. It wasn't completely one-way traffic as hyaenids also migrated in the other direction. One species of the so-called 'running hyaena' Chasmaporthes lived alongside canids in North America. It only died out following the arrival of large wolf-like Canis from Eurasia. Today we are left with only one of the dog-like forms, the specialised termite-eating aardwolf Proteles.

Not directly competing with canids allowed the bone-cracking hyaenas to maintain a dominance that continues today (some borophagine canids were also specialised bone-crackers but restricted to North America). The best known species outside living forms was Pachycrocuta. It was as heavy as a lion, despite standing only as tall as a modern spotted hyaena. Various human species interacted with Pachycrocuta, such as at the famous Dragon Bone Hill site in China where half of the Homo erectus bones show signs of hyaena gnawing. It was a less cursorial species compared to spotted hyaenas, and probably spent relatively more time scavenging carcasses than hunting. Across it's range, Pachycrocuta was replaced by the more versatile Crocuta during the Mid Pleistocene.

One group which has been a puzzle for some time are the large percrocutoids (Dinocrocuta and Percrocuta). Regularly placed as a sister family to hyaenids or linked to the basal stenoplesictines, percrocutoids were long considered a convergent durophagous lineage to hyaenas. A recent study of morphological features in Dinocrocuta appears to show that they are indeed hyaenids, but are likely to be a sidebranch. Dinocrocuta was one of the largest known terrestrial carnivorans, reaching an upper weight of 300 kgs and having a 43 cm long skull (roughly twice the length of a spotted hyaena).

Description

A selection of extinct members of the carnivoran hyaenids, to scale.

A common cultural stereotype of hyaenas is that they are greedy, stupid, cowardly and ugly. This isn't just a Western viewpoint; some stories stem from native African folklore, but it differs greatly between ethnic groups. Scavenging and robbing graves certainly doesn't tend to bestow a good name! But the reputation is misplaced as hyaenids include active apex predators, complicated clan dynamics, perform co-operative problem-solving, include secretive insect-eaters and most famously species which can crack open bones to access the marrow. Today just four species constitute the entire hyaenid family (one of the smallest mammalian families), however there is extensive fossil record with widespread diversity across over 100 named species.

Bone-cracking is a relatively recent development in hyaenids. The earliest forms from the Early Miocene originated in Europe and were insect/small veretbrate hunters. Species like Protictherium and Plioviverrops were more like civets or mongooses, even capable of climbing trees. During the Miocene, hyaenids split into two main niches: the agile dog-like forms and the heavier bone-crackers. The dog-like hyaenids, such as Hyaenotherium were very successful during the Miocene but showed a massive decline prior to the Pliocene, as canids migrated west across the land bridge of Beringia. It wasn't completely one-way traffic as hyaenids also migrated in the other direction. One species of the so-called 'running hyaena' Chasmaporthes lived alongside canids in North America. It only died out following the arrival of large wolf-like Canis from Eurasia. Today we are left with only one of the dog-like forms, the specialised termite-eating aardwolf Proteles.

Not directly competing with canids allowed the bone-cracking hyaenas to maintain a dominance that continues today (some borophagine canids were also specialised bone-crackers but restricted to North America). The best known species outside living forms was Pachycrocuta. It was as heavy as a lion, despite standing only as tall as a modern spotted hyaena. Various human species interacted with Pachycrocuta, such as at the famous Dragon Bone Hill site in China where half of the Homo erectus bones show signs of hyaena gnawing. It was a less cursorial species compared to spotted hyaenas, and probably spent relatively more time scavenging carcasses than hunting. Across it's range, Pachycrocuta was replaced by the more versatile Crocuta during the Mid Pleistocene.

One group which has been a puzzle for some time are the large percrocutoids (Dinocrocuta and Percrocuta). Regularly placed as a sister family to hyaenids or linked to the basal stenoplesictines, percrocutoids were long considered a convergent durophagous lineage to hyaenas. A recent study of morphological features in Dinocrocuta appears to show that they are indeed hyaenids, but are likely to be a sidebranch. Dinocrocuta was one of the largest known terrestrial carnivorans, reaching an upper weight of 300 kgs and having a 43 cm long skull (roughly twice the length of a spotted hyaena).