The Pomelo fruit has excellent dampening properties due to the hierarchal organization of its composite peel. Dropped from higher levels the fruit shows little to no damage on the outer layer. Analyses of thin sections of pummelo peel revealed a gradual transition in density between exocarp and mesocarp. Thus, structurally, the dense exocarp cannot be separated clearly from the spongy mesocarp. The mesocarp with its air-filled intercellular spaces represents a compressible foam, and has the ability to dissipate large amounts of energy.
The skin of Australian frogs of the genus Notaden protects from insect bites via a secreted glue. When set, it is flexible and has a porous structure that should make it permeable to gas and nutrients, which would encourage healing. The glue is secreted by two species of burrowing Australian frogs of the Notaden genus that live underground. These frogs only surface during torrential rain. At these times they are vulnerable to attack from insects. To protect themselves they secrete a glue that gums up the jaws of the biting insects and traps them to their skin, which they later eat.
Larval jewel beetles spend up to five years boring through hardwood before metamorphosing into adult beetles and emerging. The mandibles they produce must be strong enough to chew through the tough acacia wood. Most arthropods and invertebrates incorporate minerals and transition metals into such structures that demand extreme strength and hardness (e.g., beaks, jaws, shells) and this addition has been long considered crucial to their physical properties. However, the larval jewel beetle's mandible is stronger than most metal-laden biomaterials yet contains only carbon-based, organic materials. Amazingly, this material is composed of fibers of crystalline chitin sheathed in proteins that cross-link and harden.
Termite mounds. They may look like just a big pile of well-structured dirt but they are actually marvels of architecture and fill an unexpectedly important function in the ecosystems in which they appear. In fact, the areas around termite mounds can be some of the most biologically diverse in an entire habitat.