Defense structures include thorns, spines, prickles, sticky plant hairs, and high levels of silica. Nutritionally, if a plant lacks several of the 12 essential amino acids, it is less likely to be useful food. Overgrazing is prevented by these secondary compounds because they may be unpalatable or toxic to metabolic processes or development. These organisms evolved mechanisms over time that allowed them to break down the irritating compounds. By feeding on plants few to no other organisms eat, they are reducing outside competition on their food source.
Cryptic coloration provides camouflage, hiding the animal from predators.
Aposematic coloration is highly visible and indicates the presence of some defensive mechanism. An animal that stores a plant's secondary chemicals will generally be poisonous and brightly colored, whereas an animal that degrades the compounds generally will not be poisonous and may be camouflaged. Batesian mimicry describes the situation when an unprotected species evolves to resemble a chemically protected species. The purpose for the possessor is that it will not be preyed upon by those predators familiar with the model. There must be a much smaller number of mimics than aposematics.