Mackerel sharks are a group of fish characterized by an anal fin, two dorsal fins, five gill slits, and eyes that are situated behind the eyes. A crocodile shark is a type of small mackerel shark that lives in oceans throughout the world. It is a predator, dining mainly on smaller fish, squid, and shrimp. This shark is sometimes referred to as a water crocodile, Japanese ragged-tooth shark, or Kamohara's sand-shark.
The body of a crocodile shark is typically long and narrow with a slightly pointed snout and tail. Its sides sometimes appear to be flat when viewed from the front. This fish may have a slightly rounded belly and jaws.
A water crocodile is medium to dark gray in color. Scales cover the sides of this animal, which means they may appear shiny. The belly and head are usually dull. This animal's fins often have black markings on the tips, and one or both of the dorsal fins are silver.
As a rule this shark is very small, reaching only three feet (1 m) long when fully mature. An adult crocodile shark typically weighs between nine and 13 pounds (4 to 6 kg). This fish does not contain much meat, so it is rarely kept whenever it is caught.
The eyes of a crocodile shark are green or yellow with a slightly reflective covering. This covering makes it easy for this fish to see at night. It is believed this shark can detect the silhouette of its prey even when there is very little light penetrating the water. As such, it is a nocturnal animal that stays in deeper water during the day and swims in more shallow water at night.
Both the upper and lower jaw of a crocodile shark has multiple rows of teeth. These teeth are pointed on the end and serrated around the edges. Each row contains up to 30 teeth. Like other types of shark, the crocodile shark never runs out of teeth. When one is lost, a new one springs forward to take the place of the one that is dropped.
Although it is found throughout the world, this fish is more plentiful in some areas. It is not known to inhabit waters off the northeastern coast of Canada. Some common locations where a crocodile shark might be found include the Atlantic coast of South America, the Indian Ocean, and Pacific coast of Taiwan and Korea.