The pygmy shark (Euprotomicrus bispinatus) is a small, deep-sea shark found in tropical and temperate oceans. It reaches only about 27 cm in length. Notable for its bioluminescent underside, it uses this trait for camouflage and communication. It preys on squid and small fish, playing a role in the deep-sea food web.

Euprotomicrus bispinatus, commonly known as the pygmy shark, is found in the deep waters of the world's oceans. Its distribution is circumglobal, primarily in the temperate and tropical regions. These sharks are most commonly recorded in the Pacific Ocean, but they are also present in the Atlantic and Indian Oceans.

The pygmy shark inhabits deep oceanic waters, typically ranging from depths of 200 to 500 meters, but they can be found as deep as 1,500 meters. The species prefers the mesopelagic to bathypelagic zones, which are characterized by cold temperatures, low light, and high pressure.

Euprotomicrus bispinatus is adapted to a life in deep-sea environments where it preys on small fish, cephalopods, and crustaceans. This species exhibits vertical migration patterns, coming closer to the surface at night to feed and descending again during the day. Its small size and bioluminescent capabilities are adaptations to its deep-sea niche, allowing it to avoid predators and attract prey.