The development of a calcified vertebral column is the key distinguishing feature that separates the subphylum vertebrata from other chordates. During its evolution, the bony vertebrae has taken many different shapes and sizes. In mammals, the individual vertebral bodies are completely solid, with soft vertebral disks in between them to cushion the bony structures as they move within the body. In fish, the vertebral column is made of hollow vertebral bodies that encase the remnants of the soft notochordal tissue. The faces of fish vertebral bodies are concave, forming an hourglass shaped opening on the inside when sectioned laterally. The size and shape of this intervertebral opening varies greatly among bony fishes and there is little known about how these differences can affect vertebral bending. We wanted to know how the shape and volume of the intervertebral material might be influencing vertebral bending resistance. To answer this question, we performed bending tests using a material testing system on 3 different sets of vertebrae. First, we bent sections of the vertebral column of 5 different species of fish to failure. Then, we 3D-printed physical models of these same species, and tested them at a range of bending angles. Finally, we created and tested idealized models of the vertebrae. Using these data, we found that the relative volume of the intervertebral space relates to bending resistance; we found that bending resistance decreases as the volume of the intervertebral space increases. It is possible to use the relationships found in our data to estimate the bending resistance in a fish vertebrae by simply measuring the intervertebral volume from a CT scan. This has the dual benefit of enabling estimates from fossils and from specimens only available as fixed material.