Scyliorhinidae

These sharks are called catsharks.

They live on the sea floor. Most are small. Many have spots or stripes. They have eyes like a cat.

Some sharks lay eggs. The eggs are in tough cases. These look like little purses.

Some sharks can swell up. They fill their bellies with water. This makes them look big.

They hunt for food at night. They are not bad for people.

Catsharks are a family of sharks.

They are often called catsharks. This is because they have eyes like a cat. Most are small. They grow no longer than 80 cm. A few can grow to 1.6 m. Many have spots, stripes, or patches.

These sharks live on the sea floor. They eat small fish and other sea life. Some species are nocturnal. This means they hunt at night. During the day, they sleep in cracks in the rocks.

Many catsharks lay eggs. They put eggs in tough cases. These cases have curly ends. People call them "mermaid's purses." It can take a year for a shark to hatch.

Some sharks have a special way to stay safe. Swell sharks fill their stomachs with water or air. This makes them look much bigger. This helps them when they feel threatened. Some catsharks are also biofluorescent. This means they give off light. They live in warm and cool seas all over the world.

Catsharks belong to a family called Scyliorhinidae. These sharks are part of the ground shark group.

Many people also call them dogfish. You can tell them apart by how they have babies. Catsharks lay eggs to grow. Dogfish have live young instead. Dogfish also lack an anal fin. These sharks are not harmful to humans. They mostly live on the bottom of the sea.

Most catsharks have a very specific look. They have long eyes that look like a cat's eyes. They also have two small fins on their backs. Most species stay small. They grow no longer than 80 cm. A few can reach 1.6 m in length. Many have patterns like spots or stripes.

Some sharks, like the swell shark, have a neat trick. They fill their stomachs with air or water. This makes them look much wider. This helps them when they feel threatened. Some catsharks even show biofluorescence. This means they give off light.

Scientists have studied these sharks for a long time. They use different names for groups of these sharks. For example, T. N. Gill named the genus Cephaloscyllium in 1862. A. Smith named the genus Poroderma in 1838. Blainville named the genus Scyliorhinus in 1816. These names help us group the many different types.

The sharks even have a special way to grow teeth. A protein called sonic hedgehog helps shape their jaws. This protein is also found in humans. Their teeth grow back every 18 to 38 days.

Catsharks live in many different places. They live in both warm and cool seas. They can be found in very shallow water. Some live in depths of 2,000 m or more.

The red-spotted catshark lives near Peru and Chile. It moves to deeper water during the winter. The chain dogfish lives in the Atlantic Ocean. They live from Massachusetts down to Nicaragua. Adults often like soft, sandy bottoms. This is a good place to lay their eggs.

Many catsharks lay eggs in a special way. They use tough egg cases for protection. These cases have curly ends called tendrils. People often call these "mermaid's purses."

It can take almost a year to hatch. Some sharks hold the eggs for a few months before they hatch. Other species use ovoviviparity. This means they hold the embryos until they are ready. Then they give birth to live young. This helps the babies stay safe until they are strong.

The Scyliorhinidae family consists of various sharks commonly known as catsharks. These animals belong to the order Carcharhiniformes, which are called ground sharks.

While many people call them catsharks, some species are also referred to as dogfish. You can distinguish between the two by looking at how they reproduce. Catsharks are oviparous, meaning they lay eggs. In contrast, dogfish have live young and lack an anal fin. These sharks are generally not harmful to humans. They mostly live as bottom feeders, eating smaller fish and benthic invertebrates.

Physically, catsharks have several distinct features that help identify them. They possess elongated eyes that resemble those of a cat. Most species also have two small dorsal fins located far back on their bodies. Most catsharks are quite small, usually growing no longer than 80 cm. However, some species like the nursehound can reach a length of 1.6 m. Many species display colorful patterns, such as spots, patches, or stripes.

The genus Apristurus is different, featuring dark bodies and flat snouts. These sharks also have a long anal fin that ends in front of the lower caudal fin. They possess both upper and lower labial furrows as well.

Biological processes drive much of how these sharks grow and survive. For example, a protein called sonic hedgehog is involved in organ growth and patterning. In the embryonic jaw, this protein creates a bilateral symmetrical pattern for dentition. This process helps shape the teeth of the shark. Like many sharks, catsharks replace their teeth every 18 to 38 days.

Some species have unique survival mechanisms. The swell sharks of the genus Cephaloscyllium can fill their stomachs with air or water. This action increases their girth by a factor of one to three when they are threatened. Additionally, some species like the chain catshark are biofluorescent, meaning they emit light.

Scientists have organized these sharks into several different genera over time. The genus Scyliorhinus was named by Blainville in 1816. The genus Poroderma was named by A. Smith in 1838. The genus Cephaloscyllium was named by T. N. Gill in 1862.

It is important to note that the family Scyliorhinidae is paraphyletic. This means the different lineages within the family do not form a single monophyletic group. This classification helps researchers understand the complex evolutionary history of these ground sharks.

Catsharks live in a wide variety of marine environments worldwide. They inhabit both temperate and tropical seas. Their range extends from very shallow intertidal waters to depths of 2,000 m or more.

The genus Apristurus is known to live in these much deeper waters. Other species have very specific local ranges. For instance, the red-spotted catshark lives in shallow rocky waters between Peru and Chile. It migrates to deeper waters during the winter months. The chain dogfish lives on the soft or rocky Atlantic bottom from Massachusetts to Nicaragua.

Behavioral patterns among catsharks vary depending on the species. Many are nocturnal, meaning they hunt at night. Because of this, some species sleep together in crevices during the daylight hours. Some sharks are poor swimmers and do not perform long-distance migrations. Habitat segregation also occurs in species like the small-spotted catshark. In this species, males and females live in different areas. Males typically inhabit open seabeds, while females prefer to live in caves.

Reproduction in Scyliorhinidae involves several different strategies for protecting young. Many species are oviparous and lay eggs in tough cases called "mermaid's purses."

These cases have curly tendrils at each end to help them attach to the seabed. It can take nearly one year for a shark to hatch from these eggs. To protect the embryos, some species hold onto the eggs for a few months before they hatch. Other species practice ovoviviparity, which is a form of aplacental viviparity. In this process, the sharks hold the embryos until they are fully developed. They then give birth to live young. Mating can involve complex behaviors, such as males biting and holding the female's pectoral fins to wrestle her into position.