Abstract

Bioluminescence is the visible light produced by living things. These creatures are rare on land but very common in the oceans. Marine organisms can generate light using either their own luminous system, called intrinsic bioluminescence, or extrinsic bioluminescence refers to luminous bacteria that are symbiotic. Bioluminescent sharks are currently exclusively found in the Squaliformes family, primarily in the Etmopteridae, Dalatiidae, and Somniosidae families. The ventral body surface of most bioluminescent sharks emits blue light. Based on the light patterns, the biological roles of this bioluminescence have been considered, however the bioluminescence process has yet to be discovered. The squamation and physiological control of these unusual deep-sea sharks’ photogenic organs are discussed.