Skate (fish)

Skates are flat fish.

They have wide fins. These fins help them glide on the ocean floor.

Skates have rough skin. Their skin is covered in small scales. These scales are like tiny teeth.

Skates lay eggs in a case.

People call this a mermaid's purse. It keeps the babies safe.

Some babies stay in the case for a long time. They can stay there for 15 months. This helps them grow.

Skates eat small things like shrimp and crabs.

They use flat teeth to crush their food. They are very interesting fish.

Skates are flat fish with soft bodies.

Their bodies are made of cartilage. This is the same bendy material in your nose. Skates have wide fins. They use these fins to glide along the sea floor.

Skates lay eggs in a special case.

People call this case a mermaid's purse. It protects the babies as they grow. Some babies stay inside for 15 months. Some cases have one baby inside. Other cases can have up to seven.

Skates are different from stingrays. Rays give birth to live young. Skates lay eggs instead. Skates also have long, fleshy tails. They do not have the stinging spines that rays have.

Some skates have a special part in their tail. This is an electric organ. It lets out weak signals. Scientists think they might use these signals to talk to each other.

Skates like cool water. They often live in the deep, dark parts of the ocean.

Skates are amazing flat fish that live in the ocean. They belong to a group called Chondrichthyes, which means they have bodies made of cartilage instead of bone. This is the same bendy material you feel in your nose.

Most skates live on the sea floor, which is called a benthic habitat. They have wide, flat fins that help them glide through the water. This way of moving is called Rajiform locomotion.

They also use their pelvic fins to move in a way that looks like walking. This is very interesting to scientists who study how animals walk on land.

Skates have a very special way of having babies. Unlike stingrays, which give birth to live young, skates are oviparous. This means they lay eggs that develop outside of the mother's body. The eggs are tucked inside a tough, protective case.

Many people call these cases a "mermaid's purse." Each species has a case that looks a little different. Some cases have a flexible ridge called a keel. Some cases hold just one baby, while others hold up to seven embryos.

These babies might stay in their cases for up to 15 months.

Skates have been around for a very long time. They belong to an ancient group of fish. Scientists found tiny tooth-like scales called denticles that look like modern fish. These fossils date back to the Ordovician period.

Later, a group called Neoselachii appeared during the Triassic period. This group includes sharks, rays, and skates. Skates branched away from sharks about 221 to 286 million years ago. This happened because of changes in their genes that shaped their bodies.

There is a lot to learn about these fish. Scientists have described more than 150 different species. Since 1950, people have found 126 new species of skates.

The family Rajidae is very large and has about 250 valid species. Some skates live in very deep water, while others stay near the shore. Most skates like cool or polar water. They are often found on the outer continental shelves. They do not live in fresh water like lakes or rivers.

Skates have some unique tools to help them survive. They have an electric organ located in their tails.

This organ sends out weak, long-lasting signals. Scientists think they might use these signals to talk to each other for reproduction. Skates also have mouths on their undersides to eat things like shrimp and crabs. They use grinding plates in their mouths to crush their food. Even though they look like stingrays, they do not have stinging spines. Instead, they have long, fleshy tails.

Skates are a diverse group of cartilaginous fishes. They belong to the family Rajidae within the superorder Batoidea. Being cartilaginous means their skeletons are made of cartilage rather than bone. This makes them part of the class Chondrichthyes, which includes sharks and stingrays. Skates are particularly important because they are the most diverse group in the Elasmobranchii subclass. They make up more than 20% of all known elasmobranch species. Scientists have described over 150 species across 17 different genera.

The physical design of a skate is specialized for life on the ocean floor. They have a flat body shape with large pectoral fins. These fins extend along the length of their bodies. This structure allows for Rajiform locomotion, which is a type of swimming using undulating pectoral fins. This movement helps them glide across the seabed. Some species even use their pelvic fins for ambulatory locomotion, which is a form of walking. Scientists study these neural pathways to understand how animals eventually developed walking on land.

Skates possess several unique biological features. Their skin is often covered in rough placoid scales. These scales are tooth-like structures with pointed tips. Because their mouths are on the underside of their bodies, they use grinding plates to eat. They primarily consume bottom-dwelling invertebrates like shrimp, crabs, clams, and oysters. To breathe while partially buried in sediment, they use dorsal spiracles. These openings allow for respiratory exchange even when their mouths are covered. Their eyes are located on the top of their heads to watch for predators.

One of the most distinctive traits of a skate is its electric organ. This organ is found in the tail, embedded in the muscles near the notochord. Unlike some other fish, skates have paired electric organs that run longitudinally through the tail. These organs produce weak, asynchronous, and long-lasting electrical signals. While the exact function is not fully understood, researchers have several theories. The signals are likely too weak for hunting or defense. They may also be too irregular for electrolocation. Many scientists believe these impulses are used for communication during reproduction.

Reproduction in skates is quite different from that of stingrays. Skates are oviparous, which means they lay eggs. Males use structures called claspers on their pelvic fins to fertilize the female. After fertilization, a protective case forms around the embryo. This case is commonly known as a "mermaid's purse." These egg cases are excellent tools for identifying different species. Some cases have a flexible ridge called a keel. Others have very thick fibrous shells. The number of embryos inside can vary from just one to as many as seven.

Skates have a very deep evolutionary history. They belong to an ancient lineage of cartilaginous fishes. Fossil evidence shows tooth-like denticles dating back to the Ordovician period. By the Triassic period, a clade called Neoselachii had emerged. This group includes modern sharks, rays, and skates. Skates specifically diverged from sharks approximately 221 to 286 million years ago. This divergence was caused by genomic rearrangements. These genetic changes altered the three-dimensional regulatory landscape of their genes, shaping their unique body plans.

Skates are found in various habitats, mostly in marine environments. They live from the intertidal zone down to very deep waters. They are most common on outer continental shelves and upper slopes. Interestingly, skates are the only cartilaginous fish that show more diversity at higher latitudes. They thrive in cool, temperate, or polar waters. As water becomes shallower and warmer, they are often replaced by stingrays. While most avoid fresh water, one species has been found in an estuary in Tasmania. They are also found in areas with rocky relief and cobble.

It is important to distinguish skates from stingrays. While both have flat bodies and ventral gill slits, their reproductive methods differ. Rays are viviparous, meaning they give birth to live young. Skates lay eggs in their protective cases. Additionally, skates lack the whip-like tails and stinging spines found in many rays. Instead, skates have long, fleshy tails and may have electric organs. Because skates grow slowly and mature late, they have low reproductive rates. This makes them particularly vulnerable to the effects of overfishing in many parts of the world.