Stick insects use friction to grip without sticking

Research from Cambridge's Department of Zoology has revealed that stick insects produce a powerful friction to ensure they're held in place during movement. When they're not hanging upside down, stick insects don't need to stick. Sticking will actually be a hindrance to their movement, hence, they will require extra effort to 'unstick' again with every step.

By studying the 'heel pads', researchers discovered that these insects have developed a way to generate massive friction when walking upright. This is done through a system of tiny hairs in different combinations of height and curvature which create the grip

The research was published in the Journal of the Royal Society Interface and reveals another example of natural engineering.