The hero shrew — a small, ratlike animal with a bizarrely strong and oddly shaped backbone — has mystified scientists since it was first described more than 100 years ago. Now, a newly discovered species of hero shrew may help researchers piece together why the animal evolved to have such a peculiar spine and what purpose the hardy backbone serves now.
The hero shrew's unique backbone gives the animal extraordinary strength, said lead study author William Stanley, collections manager of mammals at The Field Museum in Chicago. The animal's lower back has 10 to 11 lumbar vertebrae (the bones that make up the lower spine) that jut out and interlock with one another, he added. In comparison, humans have five lumbar vertebrae between the rib cage and the pelvis that help support the weight of the body.
"The hero shrew has the most bizarre mammalian backbone in the world," Stanley told LiveScience.
For more than 100 years, the hero shrew was classified as only one species, but a new species has been discovered in central Africa that has an expanded backbone and only eight lumbar vertebrae. Although the spine appears to be slightly different from that on the original hero-shrew species, molecular evidence indicated the two are closely related, the researchers said.