Ranina ranina

This crab is reddish brown.

It has ten white spots. It has a long middle part.

The crab lives in warm water. It likes to hide in the sand. It stays under the sand during the day. It leaves its eyes out to see.

At night, it comes out to hunt. It looks for small fish. It waits in the sand to catch them.

Many people like to eat this crab. It is a special food in some lands. In Vietnam, it is called the emperor crab.

These crabs live in many places. They live in Australia and Japan. They also live in Hawaii. It is a very interesting crab.

The spanner crab is a special kind of crab.

It has a red shell called a carapace. This shell is wider at the front. It also has ten white spots. The crab has a long middle part. This helps you tell it apart from other crabs.

These crabs live in warm ocean waters. They like to stay in sandy areas. Most of the time, they hide under the sand. They do this during the day. They leave their eyes and mouths sticking out. This helps them find food. At night, they hunt for small fish.

Many people catch these crabs to eat. In Vietnam, people call it the emperor crab. This name comes from old kings who loved to eat them. You can find these crabs in many places. They live in Australia and Japan. They also live in Hawaii and Africa. Scientists study them to make sure we do not catch too many. Right now, the number of crabs is stable.

The spanner crab is a very special animal found in warm oceans. Some people call it the red frog crab or the Huỳnh Đế crab. It is a popular type of crab for people to catch and eat. This crab is easy to spot in the water. It has a reddish brown shell called a carapace. The shell is wider at the front and has ten white spots. Its middle part is also very long.

This crab has a clever way of finding its food. Most of the time, these crabs are nocturnal. This means they are active at night and sleep during the day. During the day, they bury themselves deep in smooth sand. They leave only their eyes and mouths sticking out of the ground. This helps them wait for small fish to swim by. When a fish comes near, the crab attacks from under the sand.

Many different places in the world have these crabs. They live along the east coast of Australia. You can find them from Yeppoon in Queensland to New South Wales. They also live north of Perth in Western Australia. These crabs are found in the Philippines and in Japan. They live in Hawaii and even as far as the coast of Africa. They like to live in deep, sandy areas in warm water.

People catch these crabs for food in many lands. In Australia, the yearly catch is a very large amount. In the Philippines, they were sold for 200 to 300 pesos per kilogram in 2008. In Vietnam, the name Huỳnh Đế means "emperor crab." This is because old Vietnamese kings loved to eat them. In some parts of Vietnam, they are called the "monarch of all the crab." In the Philippines, they are often eaten steamed or in coconut milk.

Scientists work hard to study these crabs to keep them safe. They want to make sure we do not catch too many. In Queensland, people only keep adult crabs that are a certain size. In Australia, 96% of female crabs are not caught by fishers. This helps the population stay healthy and stable. Scientists have tried to grow them in tanks, but it is a hard job. We are still learning much about how they live and grow.

The *Ranina ranina* is a unique species of crustacean found in warm ocean waters.

People call this animal by many names. It is known as the spanner crab, the red frog crab, or the Huỳnh Đế crab. This species is highly valued as a food source in many tropical and subtropical regions. Because it is a popular seafood, it is commercially exploited in several parts of the world. Understanding its biology and habitat is important for managing the fisheries that rely on it.

This crab has a very specific way of living and hunting. It is primarily a nocturnal animal, which means it is most active during the night. During the daylight hours, the crab seeks out smooth, sandy seafloors to hide. It uses the sand to bury its body almost completely. However, it does not hide entirely. The crab leaves its eyes and its mouthparts poking out above the sand. This allows the crab to detect movement and sense food nearby. When a small, bottom-dwelling fish swims close enough, the crab attacks from its hidden position under the sand.

The physical appearance of *Ranina ranina* makes it easy to identify. It has a reddish-brown carapace, which is the hard upper shell that protects its body. This carapace is wider at the front than at the back. It also features ten distinct white spots. Another key feature is its elongated midsection, which sets it apart from other crab species in its environment. These physical traits help it blend into its sandy habitat while it waits for prey.

These crabs inhabit a wide range of coastal waters across the globe. In Australia, they live along the east coast from Yeppoon in Queensland to the north coast of New South Wales. There is also a population located north of Perth in Western Australia. Beyond Australia, they are abundant in the waters of southwestern Mindanao in the Philippines. Their range extends across the Indian Ocean to the east coast of Africa. They can also be found in Indonesia, Japan, and Hawaii. They require environments with ample sand to flourish and use their burying method.

Fisheries play a massive role in the life of the spanner crab. The largest fishery for this species is located in Australia. In Queensland, there are specific rules to protect the population. For example, only adult crabs above a certain carapace length may be landed by fishers. In Australia, 96% of female crabs are not fished. This helps keep the species from disappearing. However, at Tallows Beach, the decrease in hunted females does not apply during the spawning season. This suggests that Tallows Beach is a specific location for spawning migrations.

In many cultures, *Ranina ranina* is considered a culinary delicacy. In the Philippines, it is known as curacha and is a regional specialty. It is often prepared as *halabos*, which means it is steamed. It can also be cooked in coconut milk in a dish called *ginataan*. A famous version of this is the *curacha Alavar* from Zamboanga City. In Vietnam, the name Huỳnh Đế literally means "emperor crab." This name comes from the fact that these crabs were favorite foods for historical Vietnamese monarchs. In the provinces of Bình Định and Quảng Ngãi, it is hailed as the "monarch of all the crab."

Even though they are important for food, scientists are still learning about them. In 2008, the price for these crabs in the Philippines was around 200 to 300 pesos per kilogram. While they are a target for commercial fishing, very little is known about their exact biology or population dynamics. Scientists have tried to grow the crabs in captivity, but these attempts have seen little success. Currently, surveys show that the populations remain stable. Researchers continue to monitor them to prevent overfishing and to better understand their complex ecology.