Skin-secreted adhesives, or glues, are highly effective defense adaptations that have evolved recurrently in a small number of amphibians. From an ecological standpoint, this rapidly solidifying material—essentially, a sticky slime—encumbers the predator long enough for its would-be prey to escape.

But what makes some skin secretions stickier than others, and why has it arisen multiple times throughout the history of amphibian evolution?

Adhesives in nature: Ancient tools for survival

There's no denying that materials that help us stick things to other things—that is, glue—are omnipresent. On any given day, you may find yourself reaching for a stack of sticky notes or a universally reliable roll of sticky tape. But what about glue in other, less dexterous animals? What is it used for, and how does it work?

Before we go any further, let's clarify what exactly is meant by "animal glue." In the context of glue-producing organisms, the materials I'm referring to are called "biological adhesives." These are naturally secreted materials that occur in a wide range of species, with many serving vital functions necessary for that particular organism's survival.

• Read More