Exoskeleton

An exoskeleton is an external skeleton that supports and protects an animal’s body. In biology, exoskeletons are characteristic of many invertebrates, especially arthropods such as insects, arachnids, and crustaceans. They provide structural support, protect soft tissues, help prevent desiccation in terrestrial species, and anchor muscles for movement. Exoskeletons are typically made of chitin and protein, and in crustaceans they may be reinforced with calcium carbonate. Growth occurs through molting, or ecdysis, during which the organism sheds its old exoskeleton and forms a new, larger one. This growth strategy can leave the animal vulnerable during the molt and imposes size-related constraints on maximum body size.

In technology, the term exoskeleton also refers to wearable devices that augment human strength and mobility. Powered exoskeletons incorporate actuators, sensors, and controls to assist leg or upper-body movement, while soft exoskeletons use flexible materials for comfort. Applications range from industrial lifting and rehabilitation to research and military development. Benefits include reduced energy cost of movement, increased lifting capacity, and enhanced rehabilitation outcomes; challenges involve added weight, battery life, control interfaces, wearability, and safety concerns.

The concept also extends to robotic systems and augmented devices where external framing provides support or form. Exoskeletons, whether natural or engineered, illustrate external support structures that interact with internal systems to enable function.