The Japanese giant salamander, also known as the big mountain pepper fish, is one of the largest amphibians in the world, second only to the Chinese giant salamander. It is mainly distributed in mountainous rivers in southern Honshu Island, Shikoku and northern Kyushu, Japan, and inhabits cold, turbulent, and high-oxygen alpine freshwater streams and rivers. The body shape is flat and long. The skin is brownish with black spots, the head is broad, and the eyes are small and degenerate, almost hidden in folds of skin. It is a nocturnal animal that hides under rocks or in caves during the day and comes out at night to prey on fish, salamanders, worms, insects and snails. It has been listed in the red list of endangered species, and its protection status is near danger.

Also known as the Big Mountain Pepper Fish, it is an amphibian species belonging to the genus Giant Salamander in the family Heterobranchidae. Its body size is relatively large, second only to the Chinese giant salamander, ranking second in the world. The body length is generally around 60 centimeters and the weight is 25 kilograms; The largest individual can reach a length of 1.5 meters and weigh 45 kilograms. Mainly distributed in mountainous rivers in parts of Honshu to western Gifu, Shikoku, and Kyushu in Japan. They usually live in cold, rocky mountain freshwater streams and rivers, with a distribution range of 300 to 700 meters above sea level. I enjoy nighttime activities and use my sense of smell and touch to search for prey, including fish, salamanders, worms, insects, crayfish, and snails.

It is an amphibian with a tail order and a family of hidden gill salamanders. It is an aquatic and nocturnal amphibian, the world's second largest baby fish with a large body size. The male has a total length of 627.5 millimeters and the female has a length of 665.1 millimeters. The head is large and flat, slightly longer than the width, with a blunt and rounded snout slightly protruding from the lower jaw; The nostrils are small and very close to the tip of the kiss; Small eyes without eyelids, large cleft mouth, and obvious lip folds at the corners of the mouth. The Chinese giant salamander and the Japanese giant salamander have very similar body shapes, with the main difference being that the former has small and regularly arranged warts on their heads, while the latter has large and irregularly arranged warts.