The eel-like hagfish is a superpowered escape artist, thanks to its slime. When threatened, the hagfish releases long protein-rich threads that, when combined with turbulent sea water, unravel to form large volumes of viscoelastic slime that clog the gills of its predators. A new study shows that larger hagfish produce longer and thicker threads in their slime, enabling them to escape larger predators than their smaller brethren can.
The properties of hagfish slime are tuned for defense. When stretched, the long protein threads resist, making the slime more viscous. Since most fish use suction methods to catch prey, that means a predator attacking a hagfish will quickly exacerbate its slimy problems. But the hagfish itself can easily escape its slime by tying itself in a knot. The threads inside the slime collapse when sheared, so the knot-tying of the hagfish slips the slime right off. (Image credit: T. Winegard; research credit: Y. Zeng et al.; via Ars Technica; submitted by Kam-Yung Soh)