Chimaeras are a species of cartilaginous fish that belong to the class Chondrichthyes, which also contains sharks and rays. They are sometimes known as ghost sharks or ratfish. They inhabit the waters of the deep ocean and have a peculiar look, consisting of a long tail that tapers toward the end, a bony-plated skull, and a poisonous spine on its dorsal fin.
Chimaeras are not usually seen by humans because of their uncommon nature and low population numbers. They are very old fish that have been alive for more than 300 million years, and scientists believe that they are the closest living relatives to the first jawed vertebrates that ever lived.
According to their diets, which include a wide variety of fish, crabs, and cephalopods, chimaeras are primarily carnivorous.They are generally slow-moving animals that spend the most of their time near the ocean floor, where they use their big, sensitive snouts to sense prey and locate where it is hiding.
Chimaeras are of interest to scientists not just because of their one-of-a-kind physiology but also because their bodies have remained mostly unchanged for millions of years. They vary from sharks and rays in that they only have one aperture for a gill slit on each side of their heads, and they also have an unusual sort of jaw that is not attached to the rest of their skull.
In general, chimaeras are interesting and enigmatic creatures that continue to pique the interest of scientists and those who are passionate about the ocean.
From wikipedia