Back pain is a common aspect of the human experience, with an estimated eight in 10 people experiencing back discomfort at some point in their lives. However, new research suggests that this problem might not be quite so human after all: one recent study shows that doctors have a difficult time telling the difference between human vertebrae taken from patients with lower back pain and those from chimpanzees. This data could reveal important information about evolution, bipedalism, and how to better treat lower back pain.

Chimpanzees have developed their characteristic crouched posture and gait because they have a difficult time walking upright for long periods: the shape of their spine is simply better adapted for quadrupedal movement. In contrast, humans have developed a number of skeletal adaptations that make bipedal locomotion possible, our spine shapes included. However, new research from scientists in Scotland, Canada and Iceland suggests that not all humans are as evolved as others when it comes to this feature.

Over the course of the study, the researchers compared the vertebrae of chimpanzees, orangutans and humans with and without back pain. The healthy human vertebrae were easy to distinguish from the chimpanzee and orangutan samples. However, the vertebrae of chimpanzees were nearly indistinguishable from those taken from humans with back pain. In terms of appearance and functionality, they were actually closer to those from the chimps than healthy humans.

“Our findings show that the vertebrae of humans with disc problems are closer in shape to those of our closest ape relatives, the chimpanzee, than are the vertebrae of humans without disc problems,”Professor Mark Collard, one of the study’s researchers, told the BBC.

However, the researchers were quick to explain that this doesn’t mean that people with lower back pain are less evolved than their healthy counterparts. Instead, evolution is a varied process, and not every group will adapt the same way. However, development has certainly occurred: those with the chimpanzee-like vertebrae will still have a range of traits that make them better suited for bipedalism than actual chimpanzees.

Despite its attention-grabbing details and data, the researchers hope that the study will help doctors better understand, diagnose, treat and possibly predict lower back pain. The study will likely also be used in future research on human evolution, and specifically the evolution of bipedalism.