Japanese giant salamander

This big salamander lives in Japan.

It stays in the water all its life. It likes cool, fast rivers.

Its skin has many folds. These folds help it breathe in the water. It has very small eyes. It cannot see very well. Instead, it feels tiny shakes in the water. This helps it find food like fish and crabs. It can live for a long time. Some may live for 80 years! It is a very special animal.

The Japanese giant salamander is a very large animal.

It lives in Japan. It can grow up to 1.5 meters long. This makes it the third-largest salamander in the world.

These animals live in cool, fast rivers. They stay in the water their whole lives. They have very small eyes and cannot see well. To find food, they use a lateral line system. This is a set of special cells on their skin. These cells feel tiny shakes in the water. This helps them hunt for fish, crabs, and worms.

Their skin has many folds. These folds help them breathe. The folds let oxygen into their bodies from the water.

During mating season, males find a den. A male becomes a den master. He cleans the nest with his tail. He also guards the eggs. He may even eat eggs that are not healthy. This keeps the other eggs safe from germs. These salamanders can live for nearly 80 years in the wild.

The Japanese giant salamander is a huge animal that lives in Japan.

It lives in the western part of Honshu, on Shikoku, and in northern Kyushu. This creature is the third-largest salamander in the whole world. Only the Chinese giant salamander and the South China giant salamander are bigger. In Japan, people call it "ando," which means giant salamander.

It is a special natural monument that the government protects.

These salamanders have a very interesting way of breathing and moving. They live in cool, fast-flowing mountain streams. Because they do not have gills, they must stay in water with lots of oxygen. They use their skin to breathe by taking in oxygen from the water. Large folds on their necks help them do this by adding more surface area.

They also have a lateral line system on their skin. This is a set of tiny, hair-like cells that feel vibrations in the water. Since their eyes are very small and they cannot see well, these cells help them find food.

People first learned about these giants in the 1820s. A doctor named Philipp Franz von Siebold captured one on Dejima Island. He sent the animal to Leiden in the Netherlands. This helped Europeans learn about the species for the first time. Today, we know they can live a very long time. In the wild, they may live for nearly 80 years. One lived for 52 years in a zoo in the Netherlands.

There are many specific facts about how they look and act. A wild salamander can grow to 1.5 meters long. They can also weigh up to 25 kilograms. Their skin is brown and black to hide in river bottoms. During mating season in August or September, males find a nesting site. The strongest male becomes a "den master" to guard the eggs.

He even uses his tail to fan water over the eggs to keep them healthy.

Even though they are protected, these salamanders face many hard jobs. Pollution and habitat loss make it difficult for them to live. Concrete banks and dams can block their paths or ruin nesting spots. Another problem is meeting the Chinese giant salamander. Since these two can mate, it creates hybrids. In the Kamo River, researchers found that 95% of the salamanders were hybrids. Groups like the Japanese Giant Salamander Society work hard to help them.

The Japanese giant salamander, known scientifically as *Andrias japonicus*, is a massive amphibian native to Japan.

It is one of only six giant salamander species in the world. This species is the third-largest salamander on Earth. It is surpassed only by the Chinese giant salamander and the South China giant salamander. In Japan, it is often called *ando*, which means giant salamander.

Because of its cultural and educational importance, the Japanese government designated it a special natural monument in 1951.

Physically, these animals are built for life in moving water. They can reach lengths of 1.5 meters and weigh up to 25 kilograms. Their skin is mottled with brown and black colors. This pattern provides camouflage against the bottoms of streams and rivers. The skin is covered in small warts, which are more concentrated on the head. Unlike many other amphibians, they lack eyelids and have very poor eyesight. To compensate, they use a lateral line system. This is a collection of sensory cells running from head to toe. These hair-like cells detect tiny vibrations in the water, much like the hair cells in a human ear. This helps them hunt in the dark.

Because they lack gills, their breathing process is very specialized. They rely on epidermal gas exchange, which means they breathe through their skin. To make this more efficient, they have large skin folds on their neck and body. These folds increase the total surface area of the skin. This allows more oxygen to enter the body and more carbon dioxide to leave. Capillaries, or tiny blood vessels, within the skin facilitate this exchange with the water. This requirement for high oxygen levels means they are restricted to clear, cool, fast-flowing mountain streams.

The distribution of the species is mostly in southwestern Japan. They are found in the western part of Honshu, parts of Shikoku, and northern Kyushu. Robust populations live in prefectures like Tottori, Hyogo, and Mie. They inhabit various freshwater environments, from small headwater streams to larger rivers 50 meters wide. Smaller adults often stay in small headwater streams. This behavior likely helps them avoid intraspecific competition, which is when members of the same species compete for resources.

The lifecycle of the Japanese giant salamander is entirely aquatic. Unlike many other salamanders, they do not move to land after metamorphosis. Instead, they remain in the water and only breach the surface to breathe air. During the breeding season in late August or early September, males migrate to find nesting sites. The most competitive males become "den masters." A den master cleans his den and guards it against other males. When a female lays her eggs, the den master stays to provide parental care. He fans the eggs with his tail to increase oxygen flow. He also performs hygienic filial cannibalism. This means he eats eggs or larvae that are dead or infected with water mold. This protects the healthy offspring from disease.

History shows how humans first encountered these giants. In the 1820s, a physician named Philipp Franz von Siebold captured an individual on Dejima Island. He shipped the specimen back to Leiden in the Netherlands. This provided Europeans with their first catalog of the species. These animals are incredibly long-lived. In the wild, they can live for nearly 80 years. One individual in a Dutch zoo lived for 52 years. They also have a very slow metabolism, allowing them to go weeks without eating.

Today, the species faces several serious conservation threats. Habitat degradation is a major issue. The construction of concrete stream banks and agricultural dams blocks migration and destroys nesting sites. Climate change also poses a risk, as more intense rainstorms may destroy stream banks. Another major challenge is introgressive hybridization. This occurs when the native Japanese giant salamander mates with the introduced Chinese giant salamander. In the Kamo River, researchers found that 95% of the population were hybrids. While the government protects them, nonprofit groups like the Japanese Giant Salamander Society work to monitor and educate the public about their declining numbers.