When a hagfish is attacked by a shark, it spews out a defensive slime that clogs up the predator’s jaws, allowing the hagfish to escape. The slime rapidly expands in milliseconds, and now we know how.
Gaurav Chaudhary at the University of Wisconsin and his colleagues modelled the hydrodynamics of hagfish slime, determining the mathematics that govern the goo. Hagfish slime is made up of mucus cells and 1-micrometre-thick thread-like fibres. Each of these fibres is about 10-16 centimetres long, and is twisted into a ball …