A super-predator once inhabited Europe, Asia and Africa, the giant short-faced hyena Pachycrocuta brevirostris. Weighing probably over 100 kilograms, it was the largest hyena ever to exist. Found in Europe since around two million years ago, it was one of the most fearsome predators faced by the first hominin populations who ventured Out of Africa; although hyenas’ direct role as ecological competitors of Pleistocene hominins is often overemphasised, they were nonetheless a unique component of the fauna encountered by these populations.

Hyenas are commonly known for their ability to break bones and feed on their contents, and Pachycrocuta brevirostris was well adapted to this feeding habit. The giant hyena was also capable of accumulating bones, as evidenced by some sites close to the heart of palaeontologists. During the Pleistocene, hominins were the only other group capable of exploiting the content of bones as a food source, using lithic tools to break them. For this reason, the possible competition of these populations with the giant hyena is of great interest to researchers. However, the reason why the species became extinct and the timing of this event in Europe has long been shrouded in mystery. 

A new study, carried out by a group of researchers from the Sapienza Department of Earth Sciences and published in the journal Quaternary Science Reviews, has reconsidered the Pachycrocuta brevirostris fossils and those of other hyenas that spread across Europe in the Pleistocene, revealing that the giant short-faced hyena disappeared from Europe around 800,000 years ago, probably as a result of climatic and environmental changes and not due to competition with other species that spread during the same period.

Previous studies have suggested that the competition generated by the arrival of Crocuta crocuta, the extant spotted hyena, may have played a role in the extinction of Pachycrocuta brevirostris. This hypothesis would be supported by the coexistence of the two species in some places where the giant hyena survived longer. However, the new research results go in the opposite direction, ruling out the hypothesis of coexistence and direct competition between these hyenas. 

“The disappearance of the giant hyena from Europe around 800,000 years ago,” says Alessio Iannucci of Sapienza, the study’s first author, “roughly coincides with the arrival of the spotted hyena, Crocuta crocuta, and another lesser-known species, "Hyaena" prisca. However, these species were only able to spread to Europe after the decline of the giant hyena and did not contribute to its extinction."

Although once widespread across the continent, the giant hyena was unable to cope with the climatic and environmental changes that occurred during the so-called "Early–Middle Pleistocene Transition". This period saw an increase in the amplitude of fluctuations between glacial and interglacial intervals and the beginning of the Ice Age. The replacement between Pachycrocuta brevirostris and the other hyenas was one of the most characteristic events of the fauna renewal at that time: several specialised carnivores, such as sabre-toothed cats, declined or became extinct, while new and more adaptable species spread. These include the lineages of modern fallow and red deer, wild boars, and wolves, as well as human populations capable of producing bifaces (hand axes).

"The species that are best adapted to particular environments or feeding strategies, such as Pachycrocuta brevirostris, are most at risk, but even those that have evolved to cope with climate fluctuations over the last million years may not be able to adapt to the rapid changes caused by human activity," concludes Raffaele Sardella of Sapienza University. "Studying the response of past ecosystems is crucial for critically interpreting the climate changes we are experiencing today."

References:

The extinction of the giant hyena Pachycrocuta brevirostris and a reappraisal of the Epivillafranchian and Galerian Hyaenidae in Europe: faunal turnover during the Early-Middle Pleistocene Transition - Alessio Iannucci, Beniamino Mecozzi, Raffaele Sardella, Dawid Adam Iurino - Quaternary Science Reviews 2021, 272:107240. https://doi.org/10.1016/j.quascirev.2021.107240

Further Information

Alessio Iannucci
Department of Earth Sciences
alessio.iannucci@uniroma1.it

Raffaele Sardella
Department of Earth Sciences
raffaele.sardella@uniroma1.it