Even though the name of this particular deepsea creature implies that it’s somehow related to sharks, there hasn’t been a common ancestor of sharks in this family for at least 400 million years.
In this article, you’ll discover some of the most interesting facts about ghost sharks, a family of fish officially known as Chimaeras that you won’t come across any time soon (unless you visit an aquarium).
1. They are a member of one particular order of fish
Ghost sharks are a member of the order Chimaeriformes in the subclass Holocephali. These are cartilaginous fish that are defined by having skeletons that are made of cartilage, a form of tissue much more flexible than bones.
The first species of this type of fish emerged over 400 million years ago, the last time that they shared common ancestry with sharks and rays.
Three are about 52 extant species of chimaeras known today which are all classified in their own order Chimaeriformes.
2. Most species live at the bottom of the ocean
Chimaeras can be found in temperate oceans all around the world. Even though some species might approach depths of just 200 meters (660 feet) most live in the utmost depths of the ocean.
This means that they are confined to depths of up to 2,600 meters (8,500 feet), a dark and mysterious world that the right of the ocean’s surface can barely reach.
There are just 2 places in the world that these fish can’t be for, which are the extremely cold Arctic and Antarctic Oceans.
3. Some species can grow pretty big
Even though the size of the fish in this order can differ quite significantly, some species can grow to a length of 150 centimeters (4.9 feet).
The “Rabbit Fish” (Chimaera monstrosa), one of the species of ghost sharks, is one of these species that can grow its long. This length does, however, include the long tail of the fish.
Most chimaeras have long bodies, a relatively large head with big eyes, and are dark brown, grey, or black in color. Their skin is smooth and naked which is perfectly suited to glide around in the depths of the oceans.
4. Many species possess an excellent weapon of defense
Perhaps one of the most remarkable facts about ghost sharks is that they have developed a defense weapon just below their dorsal fin. This weapon is a venomous spine that they can use to seriously wound and paralyze potential predators.
When it comes to being a predator, they use the same technique as sharks to lure in prey. They are capable of sending out electric signals, something referred to as “Electroreception.”
The main difference between sarks and chimaeras is that their upper jaws are directly connected to their skull. This means that they don’t possess razor-sharp teeth but 3 permanent grinding tooth plates instead.
5. Some species are known to be threatened with extinction
Numerous studies and exploration projects were conducted in the first decade of the 21st century. This has resulted in multiple new species of ghost sharks being discovered.
At the moment, 52 species are known which are divided into 6 different genera. This study also concluded that 8% of the species are classified as “threatened” and 8% are classified as “near-threatened.”
Another remarkable conclusion of this particular study was that most of the species are endemic and 37% of all discovered chimaeras lived in some particular sections of the world.
The most common areas that they were found were off the coast of Morocco in the northern part of the Atlantic Ocean, East China Sea, New Zealand, and off the northeast coast of South America in Peru and Ecuador.
More interesting facts about ghost sharks
6. Even though the official name of this type of fish is chimaera, they are commonly known as “ghost sharks.” This isn’t the only nickname that they go by, though.
Some species are also referred to as “ratfish,” “spookfish,” or even “rabbitfish.” This means that in case you hear or read about these names, they are members of the order “Chimaeriformes.”
7. Even though most species live in the depths of the ocean and are impossible to keep alive in artificial settings, some species are kept in aquariums all around the world.
These are the species that live in shallower waters such as the rabbitfish (Chimaera monstrosa), the spotted ratfish (Hydrolagus colliei), and the Australian ghost shark (Callorhinchus milii).
8. There aren’t that many fossil records of these types of fish so the classification is for the most part based on DNA sequences.
The first remains of this type of fish were found in Europe on the Luxembourg-French border and concluded that they emerged over 400 million years ago.
9. The main conclusion of the study related to these early remains is that these fish were already abundant all over the world back then.
They also were pretty common in much shallower waters back then which means they were probably forced deeper and deeper into the ocean because of predators.
10. The male chimaeras feature a reproductive organ known as a “clasper” which they use to fertilize females. This is an organ also present in sharks. The females then go on to lay eggs that are covered in a leather-like wrapping.
The rabbitfish (Chimaera monstrosa), one of the few species that are kept in aquaria all around the world and which can be studied, is known to live up to 30 years.
Little is known about the life expectancy of species living at the bottom of the ocean, but it’s certainly significantly shorter than the species living in captivity.