The sand tiger shark (Carcharias taurus), also known as the grey nurse shark or the spotted ragged-tooth shark, is a species found in the temperate and subtropical waters everywhere in the world.
They prefer the shallow waters around continental shelves, especially sandy areas – hence the name, too. They are common in the waters around Australia, Japan, South Africa and in the Mediterranean Sea as well, the only exception being the eastern Pacific, where there are no sand tiger sharks. They are also known as a migrating species – some individuals can cover 1,000 km, maybe even more.
Sand tiger sharks have bulky bodies that reach slightly more than 3 meters in length on average. Their head is pointed and sharp and they wear red spots on their back. Their large mouths are characteristically shaped, with the upper jaw being much longer than the lower one and are lined with long and strangely-shaped teeth that point in all directions and are visible even when the animal’s mouth is closed. They are excellent swimmers, but they prefer moving around very slowly. Being the only shark species that is able to gulp air, sand tigers are often seen floating on the surface of the water, looking for food to catch.
Sand tiger sharks are voracious, satisfying their enormous appetite by attacking schools of small bony fish and capturing crustaceans, squids, sometimes even other, smaller sharks. Sometimes they hunt in packs.
The mating season of sand sharks is the winter or the period right after winter, until March or April. They usually mate in the northern waters where the substrate is rocky and there are caves, too. After mating, they move further north, to warmer waters where gestation takes place, then they return to slightly colder waters where they give birth to their juveniles. Young individuals do not migrate, but during the winter they are not seen in the area where they were born, probably because they spend the period in the deeper layers of waters.
Female sand tiger sharks have two uterine horns and they are able to keep 50 fertilized eggs inside their bodies. During the first stage of development, the embryos thrive on the nutrients they extract from the egg yolk that surrounds them. When an embryo reaches 10 cm in length, it starts eating the other, smaller embryos until only one embryo remains. Gestation lasts for about 1 year and it happens every two years.
Sand tiger sharks have a very slow growth rate. They are about 1 meter long when they are born and they grow at a rate of approximately 27 cm during the first year. After that, growth slows down to about 24 cm a year, then further, to about 7 cm a year until the juveniles reach their full length of about 2.5 meters. The sand tiger shark reaches sexual maturity around the age of 5-7.