Sleeper Sharks

The Somniosidae are a family of sharks in the order Squaliformes, commonly known as sleeper sharks. The common name "sleeper shark" comes from their slow swimming, low activity level, and perceived non-aggressive nature. They lack nictitating membrane and some species are heavily associated with Ommatokoita elongata, potentially bioluminescent parasitic copepod, permanently attached to the corneas, that frequently leave the sharks partially or completely blind. The family is believed to have arisen during the Late Cretaceous period roughly 92.29 Ma.