Shrews and hedgehogs are related but hero shrews have unusual and strong vertebral column. According to a study, a quarter-pound shrew can carry a fully grown man thanks to its evolved interlocking backbones that makes its spine strong.

Biologists in the US took CT scans of shrew spines to learn more about their mechanisms. They are not yet sure why the tiny animals developed such unique backbones. But their findings show that a shrew's super-strong spines can support considerable force from head to tail. In theory, shrews use their spines as a brace to force open palm tree trunks to get insects to eat, so maybe that is how they developed such bizarre backbones.

Crazy-looking spines

Paper author and biologist Stephanie Smith of the Field Museum and the University of Chicago said that hero shrews have crazy-looking backbones.

"Their vertebrae are squished flat like a pancake, and they have a bunch of extra places where they touch the vertebrae next to them. It makes a really long stiff column along their back and there aren't good field reports as to what this structure might be useful for," Smith said.

That is what makes the scientists curious and make them want to figure out how the hero shrews could have been using them, MailOnline reported.

Although the western scientists only became aware of hero shrews around a century ago, the Mangbetu people of Congo Basin have long known of the hero shrews' incredible strength. According to history, American and European scientists were shown by Mangbetu people how a man can stand on a hero shrew's back without hurting it.

There are two different species of hero shrews and the second one was discovered in 2013, both species of hero shrews are poorly known, according to author and paleontologist Kenneth Angielczyk of the Field Museum.

Researchers have not yet spot shrews in the wild putting their special backbones to good use. The animal is just hard to find and lives in areas where political unrest makes research trips almost impossible.

There are just specimens of the hero shrews in a museum, but they have not seen them in action yet. It is like studying an animal in the fossil record, wherein they can only study it using specimens but not bring the live version into the lab to observe it.

Experts believe that hero shrews use their spines as a brace when they shift logs and peel apart palm stems to get insects. However, since no one has observed them doing it, no one also can confirm that behavior.

Hero shrews' spines are arched, so when they contract their muscles to squeeze their vertebrae together, the bones interlock really tightly and becomes one solid block of vertebrae instead of a bunch of bendy pieces, according to Smith.

What makes their backbones sturdy?

From the museum's collection, the team of scientists took micro-CT scans of the bones of both two hero shrew species as well as an ordinary shrew for comparison. The scans revealed small details of bones, alongside hinting at how the bones most likely were used.

Smith explained that bones contain a record of forces that are acting on them during life. Signals are sent to the bones to reorganize to better handle the forces they are under. That is how bones respond throughout an animal's life to habitual forces.

The researchers found that the two species of hero shrews have a very thick, dese, and spongy bone inside their vertebrae that the percentage of bone is high relative to the total volume of the structure. That makes their bones sturdier compared to other shrews.

They published their study in the journal Proceedings of the Royal Society B: Biological Sciences.