Inside a hollowed cave in Saudi Arabia, a mysterious massive pile of bones, with human remains collected over the years. The sheer number of bones store inside this lava tube is staggering and raises questions about how it got there.

The geologic structure is a cave created from flowing magma, a lava tube with this magnificent store remains. Nudging scientists to solve the riddle of the cave and its contents.

Its exact location in Saudi Arabia is right under the volcanic fields in Harrat Khaybar in the northwest sector.

Remains discovered inside Umm Jirsan

Umm Jirsan is the longest known lava tube in Arabia that extends over 1.5 kilometers. Animals in the wild have used these immense caverns for one reason or another.

An investigation of the caves has revealed a huge pile of animal bones in the hundreds that have been identified as coming from cattle, horses, camel, and even rodents included, with a few human bones thrown in, noted Springer Link.

According to zooarchaeologist Mathew Stewart from the Max Planck Institute in Germany, the almost 2 km lava tube has countless specimens of bones in good condition, posted on Twitter.

One of the hypotheses about the caves' many bones and how they got there is the scavenged remains of the extinct Striped Hyena. Skeletons of the animal were found scattered inside the lava tubes; also, researchers discovered their fossilized poop. This mysterious massive pile of bones, with human ones, is quite interesting too.

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Stewart added that these carnivores collected bones taken to their dens for eating, food for young, or just left there for ages. All the bones stockpiles came from countless years these Hyenas were still alive, reported Sciencealert.

Researchers approximate that the Umm Jirsan tubes have kept all the bones inside, the last 7,000 years. Analysis of the cavern shows it has the best conditions to keep bones in pristine conditions.

It has been known that animal bones were in the tube before; no attempt to classify the preserved remains has been attempted. Another question that should be answered is how the ancient environment was before now.

It is still an active hyena den despite the study revealing it used to be an ancient lair. One of the earlier scientific probes of the lava tube during 2007, the expedition members had heard growling in the confines of the cave. To this modern day, the carnivores are still gathering bones like their ancestors.

Umm Jirsan Cave must have sheltered carnivores

More than hyenas could have created the bones collected, maybe foxes and wolves as well. Although, these scavenging carnivores are likely because of how the bones are found in the cave. Neither can a fox eat more oversized prey items.

Bones have bit marks and have been digested that point to the scavengers.

An assumption of the study is the large numbers of ungulate bones and the fossilized dropping makes it a likely Stripped hyena den. Also, for rearing young as well.

Umm Jirsan and its mysterious massive pile of bones, with humans, are foreboding when considered. But it is a snapshot of the past of Saudi Arabia. Stewart says it is just the beginning.

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