Asiatic Salamanders: Hynobiidae

Asiatic salamanders hunt for food at night. Scientists know little else about how these salamanders behave outside of breeding season. The breeding season varies from late winter to early summer. Some Asiatic salamanders breed in late winter and early spring. The eggs develop in ice-cold water mixed with ice and snow. Others breed in early summer. The breeding season may be as late as July for some species in western China.

Males of all but one species of Asiatic salamanders release sperm into the water while the females are laying sacs of eggs. The exception is male Semirechensk salamanders, which place sacs of sperm on rocks or plants. In all species, fertilization (FUR-teh-lih-ZAY-shun), or the joining of egg and sperm to start development, takes place outside the body. The females lay two groups of eggs, one batch of eggs coming from each ovary. The ovaries (OH-vuh-reez) are the organs that make eggs. The eggs are contained in jelly-like sacs, which attach to rocks or plants in ponds, streams, or marshes. Egg sacs that do not attach to something usually are not fertilized (FUR-teh-lyzed). The number of eggs in each sac varies, ranging from three in Japanese clawed salamanders to 105 in Siberian salamanders.

In most species of Asiatic salamanders the female chooses an object such as a rock or plant, grasps it firmly, and lays her egg sacs on it. The sacs stick to the rock or plant. After she releases part of the egg sac, the female lets go of the plant or rock and floats backward. A male waiting nearby immediately moves onto the egg sac. The male often pushes and kicks the female with its legs and presses on the egg sacs with its cloaca to fertilize the eggs. The cloaca (kloh-AY-kuh) is a chamber in both males and females that holds waste from the kidneys and intestines as well as eggs and sperm before they are released to the outside. The male's activity may help to speed up egg laying. Male clouded salamanders guard and vigorously defend the egg sacs they have fertilized.

Most Asiatic salamander eggs hatch in three to five weeks, depending on the temperature. The larvae of some salamander species that are not well developed when they hatch have a balancer on each side of the head. The balancers, which look like whiskers, support the head until the front legs develop, and then they fall off. The larvae of most stream-breeding Asiatic salamanders are well developed when they hatch and do not have balancers.