The Japanese giant salamander (Andrias japonicus) is one of the largest amphibians in the world, growing to a length of up to 1 m. It is endemic to Japan and only found within a limited area around the edge of Amami Oshima island where it lives in cool streams surrounded by beech forests and coniferous plantations.
It can weigh in at more than 100 pounds. The creature lives completely underwater during its adulthood, but it spends its early years partially submerged in water before fully developing lungs. The Japanese giant salamander is fully aquatic and requires cool, clean water to survive. Its diet consists mainly of freshwater crustaceans, insects, and fish. Habitat loss and degradation are the biggest threats to this species.
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Physical characteristics
The Japanese giant salamander is considered the largest salamander species in the world when it comes to average length; about one meter with outliers to almost one and a half meters. A specimen of the Chinese giant salamander (Andrias davidianus) of 180 centimeters was once described, but on average this species is much smaller.
The Japanese giant salamander has a rather round, slightly flattened body with a very flat, warty head. The legs are short and thick, and have large fingers, the tips of which are very tactile. The color is gray-brown to almost black with lighter or just darker jagged spots all over the body; the belly is lighter to light gray.
The tail is strongly laterally flattened and covers about a third of the body. On top of the middle of the tail, a low fin-like widening can be seen, and along the flank a thin fleshy fold of skin runs from behind the eye to the hind legs, in which there are oxygenating cells similar to gills of a fish.
Distribution and habitat
The Japanese giant salamander is a quiet and sluggish animal that lives in shallow, preferably fast-flowing and cool mountain streams and rivers on some Japanese islands.] The salamander leads a hidden existence in the mud or among the rocky rocks at the bottom, exiting the water only when the spring dries up, but is often too heavy in old age to move on land. This species is also much more water-bound than other salamanders because the animal is neotenic; the larva does not lose the typical juvenile characteristics, but can reproduce. However, the salamander must breathe regularly at the surface.
The species is threatened by human activities and is protected by CITES, but since it is considered a traditional medicine and a delicacy, the salamander is still hunted, and deforestation and pollution also do the species no good.
Way of life
The Japanese giant salamander eats small crustaceans, fish, larger insects and their larvae, worms and amphibians; basically anything it can gobble up. Males are very fierce against conspecifics during mating season; in fact, most specimens found are dead or injured males.
The giant salamander lives in the wild waters of streams and rivers as well as in the freshwater ponds and marshes of much of mainland Japan It lives exclusively in the water, where it crawls around on the bottom, lurking for prey. It eats crustaceans, fish and frogs that pass by at its height by literally sucking them up into its large mouth.
The giant salamander continues to grow throughout its life and can become very old; however, it is not known exactly how old. A captured specimen brought to the Netherlands around 1830 lived first for ten years in the Rijksmuseum of Natural History and later in the Amsterdam zoo Artis. Here the animal died in 1881 at an age of at least 51 years.
