The mechanics of mammalian intervertebral joints are complicated by the viscoelastic nature of the
connective tissues joining vertebrae, and by multiple vertebral articulations and complex morphologies.
Further, interspecific variation in these structures can greatly compound their functional variation between
species, making comparative mechanical analyses even more difficult. Despite these sources of variation
however, mammalian intervertebral joints universally exhibit a creep relaxation behaviour based on the
viscoelastic nature of the soft tissue joint. We have evaluated, in 6 degrees of freedom, the mechanical
signature of a novel mammalian lumbar intervertebral joint found in the Scutisorex spine, and compared it
with a more typical mammalian joint in the Rattus (rat) lumbar spine. Scutisorex, the hero shrew, is an East
African species of shrew with what is likely the most highly modified vertebral morphology in the entire
history of mammals. Thus we decided to evaluate the mechanical behaviour of the intervertebral joint of this
species, comparing it with a more representative mammal species in Rattus. We built a custom, 6 degrees of
freedom, intervertebral joint transducer and a combined axial moment and load application system in order
to quantify and compare the complex mechanical behaviour of these joints. Our results suggest that the
Scutisorex joint is 5 times more resilient to simple axial torsion per body mass unit than Rattus, and that the
complex load (combined axial compression and torsion) mechanical signature of Scutisorex is probably
novel among all mammalian intervertebral joints. Under significant but physiological axial compression the
Scutisorex intervertebral joint demonstrates no creep relaxation behaviour, simulating the mechanical
behaviour of a rigid construct rather than a viscoelastic joint. The purpose of this rigid intervertebral joint
in the ecology of Scutisorex remains unknown.