Pachycrocuta

Pachycrocuta is an extinct genus of hyena. The largest and most well-researched species is Pachycrocuta brevirostris, known as the giant short-faced hyena. This hyena stood about 90–100 cm (35–39 in) tall at the shoulder and weighed around 110 kg (240 lb), almost as big as a lioness. It is the largest known hyena that scientists agree on.

Scientists think this hyena may have been a special kind of scavenger. It probably used its big size to chase other predators away from dead animals so it could eat. Some scientists also believe it might have hunted in packs, similar to the spotted hyenas we see today.

Pachycrocuta brevirostris appeared during the Early Pleistocene, around 2.6 to 2 million years ago. It disappeared from Europe about 800,000 years ago but continued to live in East Asia until at least 500,000 years ago, and maybe even longer in other parts of Asia. Scientists have many ideas about why it went extinct, such as changes in the climate or the disappearance of another animal, the saber-tooth cat Megantereon.

Taxonomy

The first fossil of the short-faced hyena was found in Le Puy, Auvergne, France, in 1845. French scientist Paul Gervais named it a new species in 1850. Later, another scientist made a mistake in naming it, which lasted for many years until it was corrected in 2013.

For a long time, this hyena was grouped with modern hyenas. In 1938, a new idea suggested putting it in its own group, Pachycrocuta, and this idea became popular in 1970. Many more fossils of these hyenas have been found across Europe and Asia. Scientists have named several different kinds, but they often agree on just one main European type. The exact family tree of these hyenas compared to modern ones is still being discussed by scientists.

Description

Pachycrocuta brevirostris was one of the largest hyenas, only Dinocrocuta gigantea (which may be a true hyena or a member of the closely related extinct family Percrocutidae) grew larger. These hyenas stood about 90–100 cm (35–39 in) tall at the shoulder and weighed around 100 kilograms (220 lb), with some even reaching up to 150 kilograms (330 lb). Their legs were strong but shorter at the ends, which helped them carry heavy pieces of meat. They had large skulls and strong muscles, along with teeth built for breaking tough bones.

Behaviour and ecology

It is believed that Pachycrocuta lived in groups, much like modern spotted hyenas. Scientists have found many bones at places like the Zhoukoudian cave site in Northern China, suggesting these hyenas used caves as homes for thousands of years. Similar findings exist in Spain and Pakistan.

Some think Pachycrocuta were scavengers, using their big size to chase other animals, like sabertooth cats such as Homotherium and Megantereon, away from dead animals. Others believe they could also hunt in groups, catching medium to large animals. They were strong enough to hold down their prey.

These hyenas ate many types of animals, including mammoths, horses, rhinoceroses, deer, and bison. Evidence shows they even ate monk seals.

Scientists have studied old fossilized poop and found that these hyenas carried parasites like flukes, tapeworms from the genus Taenia, and worm-like parasites called nematodes from the groups Toxocara and Capillaria.

Relationship with humans

Pachycrocuta brevirostris likely shared the same food sources as early humans in Europe, such as Homo antecessor, and they may have competed for meat left on carcasses. Evidence from a mammoth carcass in Spain shows both humans and these large hyenas fed on the same animal. Bite marks on a skull from Georgia and bones from a cave in China suggest that Pachycrocuta may have eaten early humans, though it is not certain if they hunted them or just scavenged their remains.

Evolution and extinction

The oldest fossils of Pachycrocuta come from the Pliocene period in East Africa. The species P. brevirostris likely developed in Asia from an earlier species called Pliocrocuta perrieri. The earliest fossils of P. brevirostris in Europe are about 1.8 to 2 million years old. When Pachycrocuta arrived in Europe, it marked a time when many animal species in Europe changed or disappeared, likely due to colder weather.

P. brevirostris disappeared from Europe around 800,000 years ago. Some think it may have gone extinct because spotted hyenas arrived and were better at eating bones or lived in bigger groups, but this idea is debated. The more likely reason is that climate changes made it harder for many large animals to survive. The disappearance of other animals, like the sabertooth cat Megantereon, which may have provided food for Pachycrocuta, might also have played a role. The latest fossils of Pachycrocuta in East Asia are from about 500,000 years ago, and it may have survived longer in other parts of Asia.