Hagfish

Hagfish are jawless marine vertebrates that feed mainly on dead or dying animals. When threatened, they release mucus and protein fibers that expand into copious defensive slime.

Hagfish slime: A rapidly expanding mixture of mucus and protein fibers that hagfish release when threatened. Its water-filled network can clog a predator’s gills and help explain the hagfish’s distinctive defense.
Vertebrate: An animal with a backbone or an evolutionary precursor to one. Hagfish are vertebrates despite lacking the familiar bony backbone of most vertebrate animals.
Myxini: The class of jawless marine vertebrates that includes all living hagfish. Myxini is the taxonomic group containing the animals called hagfish.
Hagfish slime fibers: Long protein threads released as part of hagfish defensive slime. Their strength and fine diameter have prompted research into biodegradable fiber materials.
Vertebral column: A series of vertebrae forming the backbone in most vertebrates. Hagfish lack true vertebrae, raising questions about which traits define vertebrates.
Hagfish feeding: The scavenging and predatory behavior by which hagfish consume carrion and weakened animals. Hagfish use tooth-like structures and flexible bodies to feed on carcasses, sometimes entering them through openings.
Cyclostomata: A group of jawless vertebrates comprising hagfish and lampreys. This group places hagfish among the living jawless vertebrates.
Palaeospondylus: An extinct Devonian vertebrate known from small, enigmatic fossils. Its debated affinities illustrate how difficult it is to place ancient jawless vertebrate fossils.
Biomimicry: The use of biological structures and processes as models for human designs. Researchers study hagfish slime as a model for lightweight, water-responsive materials.
Deep-sea ecology: The study of organisms and ecological processes in the deep ocean. As scavengers, hagfish help consume carrion in deep-sea ecosystems.

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