Integument of soft-bodied animals is often a very interesting biomaterial. Besides unfolding and stretching to accommodate growth, it may function as a body pressure monitor in some instances. More specifically, the viscoelastic effect of the Manduca body wall prevent stress from building up as the body volume increases. When the caterpillar lost body volume, the body wall will automatically shrink to maintain the body pressure. The above effect might sound like a typical barometric reflex in mammals, except that this is done via the passive properties of the cuticular integument. Indeed, a simple reflex may be substituted by a smart material! The following graph shows the "adaptation" response found in the body wall, muscles, and the stretch receptor organ lining along the body axis. More detailed experimentation on caterpillar body pressure is ongoing.