What are Ghost Sharks?

About Ghost Sharks:

• Ghost sharks, also known as chimaeras and spookfish, are a group of cartilaginous fish closely related to sharks and rays.
• They genetically diverged from their shark relatives nearly 400 million years ago. 
• Features:
  • They have long, tapering bodies and incredibly large heads.
  • The ghost shark’s maximum observed length is about 49 inches, but scientists believe they can grow to be more than six feet in some cases. 
  • Their skin ranges in color from black to pale blue to brownish grey.
  • They have haunting black eyes and smooth, light brown, scale-free skin.
  • Their eyes are backed with a reflective tissue layer that makes them seem toglow in the dark, contributing to an eerie—even ghostlike—appearance.
  • They live at depths ranging from 200 meters to 2,600 meters and generally stay close to the seafloor.
  • Their diet primarily consists of shellfish, mollusks, and worms that live on or under the seafloor. 
  • They are sometimes referred to as the ocean’s butterflies for the way they glide through the water with their large pectoral fins.
  • Ghost sharks are thought to be solitary animals, as they are generally observed alone.

Q1: What are Sharks?

Sharks are fishes and most have the typical fusiform body shape. Like other fishes, sharks are ectothermic (cold-blooded), live in water, have fins, and breathe with gills. However, sharks differ from Osteichthyes fish. One difference is that a shark's skeleton is made of cartilage instead of bone. Another visible difference is that bony fish tend to have a single gill slit, whereas all but two species of shark have 5 gill slits.

Source: All about rare ghost shark species found in Pacific waters