Asiatic Salamanders: Hynobiidae

Physical characteristics: Hokkaido salamanders are 4 to 7 inches (10 to 18 centimeters) long. There are eleven or twelve grooves along the sides of the body, and the tail is long. The legs and toes are long compared with those of other Asiatic salamanders. The back is dark brown with a few blurry spots. Some Hokkaido salamanders keep the larval body form even though they grow to adult size.

Geographic range: Hokkaido salamanders live on Hokkaido, the northernmost of the main islands of Japan.

Habitat: Hokkaido salamanders live less than 6,600 feet (2,000 meters) above sea level. During the breeding season they live in slow-moving streams and ponds. When they are not breeding, these salamanders live on land under grass, rocks, and leaf litter on the forest floor but often visit bodies of water.

Diet: The larvae of Hokkaido salamanders eat small water-dwelling invertebrates. Adults eat insects, crustaceans, water worms, and, Hokkaido salamander larva finish metamorphosis within one year, but if the water is cold, metamorphosis can take two or even three years. (Photograph henk.wallays@skynet.be. Reproduced by permission.) sometimes, fish. Crustaceans (krus-TAY-shuns) are water-dwelling animals that have jointed legs and a hard shell but no backbone. Hokkaido salamander larvae packed close together in large groups sometimes eat other Hokkaido salamander larvae but usually do not eat their brothers and sisters.

Behavior and reproduction: Scientists know how Hokkaido salamanders reproduce but little else about how these salamanders behave. Breeding starts when the snow begins to melt and the water temperature is 37 to 41°F (3 to 5°C). In most areas, the breeding season is in April, but at higher elevations, breeding may not start until early June. Both male and female Hokkaido salamanders travel to and gather at their breeding sites. Mating and egg laying take place at night. The females lay two egg sacs, which attach to twigs and grass. Each egg sac usually contains thirty to fifty eggs, but there may be as many as ninety-three eggs in a sac. Larvae finish metamorphosis within one year, but if the water is cold, metamorphosis can take two or even three years.

Hokkaido salamanders and people: Hokkaido salamanders have no known importance to people.

Conservation status: Hokkaido salamanders are not considered threatened or endangered. ∎