Unlike Metapod and Kakuna who sit immobile and helpless in trees, their only defense a hard shell which can be broken by most pokemon given sufficient persistence, Silcoon are capable of escaping from battle. They rarely run from pokemon trainers, for they prefer the safety of a pokeball to the danger of the wilderness, yet the danger which they fear does not come from other pokemon.
The silk bodies which Silcoon possess are thought to be an adaptation to make themselves as unappetizing as possible, for in this phase these pokemon have no natural predators. Yet silk's usage in comfortable clothing has made them an alluring target for Man; they were once so commonly hunted for it that it is from Silcoon that silk gets its name. Early artifacts show Silcoon as ovals, noticably lacking the few stray strands so common in modern depictions. From the late Heian period until the early Sengoku era, there is no evidence of a single Beautifly in all of Hoenn; the only Silcoon were unfortunate Wurmple born of Dustox mothers, and they were soon harvested by hunters.
Modern Silcoon survived not because of evolution, but because of a technique whose development is still too far in its infancy for them to use it in battle, although Cascoon have mirrored it in shape as a delivery method for Poison Sting. By spinning threads together, they learned to create an ever-shifting number of spiky silk limbs, which modern Silcoon use to swing across branches and run along the ground to escape danger. Their evasive skill is an even match for human ingenuity, for although Silcoon hunters are as numerous as ever, Silcoon are once again as numerous as Cascoon in the wild; the hunters are no more dangerous than Cascoon's natural predators.