Steel-Strong Spines Could Make Hero Shrews Predator-Proof Predators

News from the Natural World: Hero Shrews - This week we have a special guest post from aspiring writer and conservationist David Duarte Crespo.

In 2013, a “sister species” was discovered: Thor’s hero shrew (Scutisorex thori). Alas, they never found a miniature hammer to go along with it. Despite this disappointment, I’d like to think Chris Hemsworth read about the new species and its name and smiled to himself. 

Unlike its sister species, it only (I say only) has eight lumbar vertebrae with fewer, but bigger processes that also interlock

Despite these discoveries, nobody knows what evolutionary purpose the spine of the hero shrews serves. Studying them is a challenge for simple two reasons: they’re quite skittish and the justifiable fact that most scientists don’t like being shot at. 
If you’re anywhere in the DRC, there’s a higher than average possibility of that happening. What with the decades of armed conflict.

What Are the Current Hypotheses?

The most widely accepted hypothesis (and the only current one) is one by Lynn Robbins. In a conversation with Stanley at a meeting of the American Society of Mammalogists, Robbins explained how he came up with his conclusion

While in the Congo rainforest, locals took him to specific locations that all had palm trees where beetle grubs are regularly collected. There, residents had captured hero shrew specimens. The locals then told Robbins the shrews are often seen running around the tree bases while they collect their literal grub.  

He thought maybe the backbones are used as crowbars to nudge themselves between the leaves and trunks of the palm trees. They arch their backs to pry the leaves out of the way and then get to the otherwise unreachable food sources
Robbins, Stanley, and other researchers discussed the hypothesis in a paper published in the Royal Society in 2013. Although Stephanie Smith, a mammalogist also from the Field Museum, points out that nobody has actually documented the shrews using their spines this way.

What’s My Hypothesis?

My hypothesis and the one of Robbins and Stanley aren’t mutually exclusive. Hero shrews could use their spines for more than one purpose. 

They evolved sturdy spines to move objects (e.g. palm tree leaves, rocks and logs) to access inaccessible food sources. Beetle grubs up in the palm trees; earthworms and various insect larvae underneath logs and rocks. These were once off-limits to predators because of their inaccessibility. Keyword: once. 

I also believe the bizarre backbones evolved to provide their owners with more escape routes. Just like how these hunters can move objects to hunt, they can do so to avoid being hunted. 

After all, if a hero shrew can carry 72 kg of man, surely it can lever a rock or fallen tree trunk to hide underneath when faced with danger.

As well as being very strong, the spine of a hero shrew is very flexible. Observations of a few captive specimens’ movements indicated the species is capable of turning the spine 180° in tight spaces via “sagittal flexion of the spine”. I had to Google those first two words.  

Said flexibility allows for hero shrews to turn more easily in claustrophobic conditions like when they’re hiding under a log or rock.     

Smith states that due to their robust ribs and preference for earthworms, hero shrews are “at least a semi-subterranean forager”. This implies they may be able to dig and thus might retreat underground as well. 

Their spines would handle the pressure of soil accumulating on them and the weight of whatever is above ground. 

I don’t think the shrews are too bothered by hiding under a rock or underground. Because it’s either that or being caught by a predator like a random tribesman who wants to try and do the Tree Pose on one of them.


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Find out who the Platypus is – here

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