Shark Crossword Puzzle for Kids

Sharks are a superorder of fish. This superorder is also known by its scientific name Selachimorpha.

Like other Chondrichthyes, sharks have skeletons made of cartilage instead of bone. Cartilage is tough, rubbery material which is less rigid than bone. Other cartilaginous fish include skates and rays.

There are more than 350 different kinds of sharks, such as the great white and whale sharks. Fossils show that sharks have been around for 450 million years, since the late Ordovician period. That is 200 million years before the dinosaurs existed.

Most sharks are predators: they hunt and eat fish, marine mammals, and other sea creatures. However, the whale shark - the largest fish in the world - eats krill, like true whales.

It is widely believed that sharks are "silent killers". However, a recent study shows that sharks emit a low growl from their throats which resonates through their scales.

Characteristics

Sharks come in many different shapes and sizes, but most are long and thin (also called streamlined), with very strong jaws.

Sharks have skin covered in millions of tiny teeth-like scales that point to the tail. If you rub along a shark towards the tail, it feels smooth, but if you rub the other way, it is rough.

Sharks' teeth are constantly replaced throughout their lives. Sharks eat so violently they often break a few teeth, so new teeth grow continuously in a groove just inside the mouth and move forward from inside the mouth on "conveyor belts" formed by the skin which they are attached to. In its lifetime, a shark can lose and regrow as many as 30,000 teeth.

Even with all those teeth, though, sharks cannot chew. So they bite their prey and jerk it around so they can pull off a chunk to swallow. The chunks of food that a shark swallows end up in its stomach, where they are digested. This is a slow process, however, so a meal might take several days to digest. This is why a shark does not eat every day.

Sharks have different-shaped teeth, depending on what they eat. For instance, some sharks have sharp, pointy teeth, while bottom-dwelling sharks have cone-shaped teeth for crushing shells. Because there are so many different kinds of sharks, and because each kind has its own kind of special teeth, many people enjoy collecting shark teeth.

Senses

Sharks have keen olfactory (smelling) sense organs in the short duct between the front and back nasal openings. They can detect blood from miles away: as little as one part per million of blood in sea water may be enough.

Sharks can determine the direction of a certain scent based on the timing of scent detection in each nostril.Jayne M. Gardiner, Jelle Atema 2010. The function of bilateral odor arrival time differences in olfactory orientation of sharks. Current Biology 20 (13), 1187-1191 This is similar to the method mammals use to determine direction of sound. Some species, such as nurse sharks, have external barbels that greatly increase their ability to sense prey.

Sharks are attracted to the chemicals found in the intestines of many species. For this reason, they often linger near or in sewage outfalls.

Shark eyes are similar to the eyes of other vertebrates; they have similar lenses, corneas and retinas. Their eyesight is well adapted to the marine environment. They can contract and dilate their pupils, like humans, something no teleost fish can do. A tissue behind the retina reflects light back, thereby increasing sight in darker waters.

Sharks have tiny holes all over their snouts, especially between the eyes and the tip of the snout. Inside these holes are nerve receptors called the ampullae of Lorenzini. p23 They can sense electricity in the water.

Reproduction

About 70% of all known shark species give birth to live young, with the gestation period lasting from 6 to 22 months.

Baby sharks (called pups) are born with a full set of teeth, and are capable of taking care of themselves. Once born, they quickly swim away from their mothers, who sometimes feed on the pups. Litters vary from one or two pups (as with great white sharks) to one hundred pups (blue sharks and whale sharks).

Some sharks are oviparous and lay their eggs in the water. Shark eggs (sometimes called "mermaid's purses") are covered by a tough, leathery membrane.

Most sharks are ovoviviparous, meaning the eggs hatch inside the female's body. The babies develop within the mother, but there is no placenta to nourish the pups. Instead the young feed on the egg's yolk. The pups eat any unfertilized eggs and sometimes each other. Very few pups in a litter survive until birth due to this form of sibling cannibalism.

Great white sharks, mako sharks, nurse sharks, tiger sharks, and sand tiger sharks give birth this way.

New shark discoveries

New sharks are still being found. Dave Ebert found ten new species in a Taiwan market. Over the past three decades he has named 24 new species. They include sharks, rays, sawfish and ghost sharks these cartilaginous fish are all related.

Fishing

Some sharks are not endangered, but some are hunted for food (like shark fin soup) or sport fishing. In 2013 five species of shark, along with two species of manta ray, received international protection as part of the Convention on International Trade in Endangered Species.

It is thought that 100 million sharks are killed by commercial and recreational fishing.HowStuffWorks "How many sharks are killed recreationally each year - and why?". Animals.howstuffworks.com. Retrieved on 2010-09-16. Sharks are a common seafood in many places, including Japan and Australia.

In the Australian state of Victoria, shark is the most commonly used fish in fish and chips, in which fillets are battered and deep-fried or crumbed and grilled. In fish and chip shops, shark is called "flake".

In India, small sharks or baby sharks (called sora in Tamil and Telugu languages) are sold in local markets. Since the flesh is not matured (not adult), cooking the flesh breaks it into powder. The powder is then fried in oil and spices (called sora puttu/sora poratu). The soft bones can be easily chewed. They are considered a delicacy in coastal Tamil Nadu.

Shagreen

Shagreen is a fabric made of shark skin. It is often described as being an untanned leather, often dyed green.

Text adapted from the Simple English Wikipedia article “Shark” (revision 10887500, 2026-06-14), authors, licensed under CC BY-SA 4.0.