sensory cells' hair-like shapes detect minute vibrations in the environment, and are quite similar to the hair cells of the human inner ear. This feature is essential for hunting prey due to its poor eyesight. Adults feed mainly on freshwater crabs, other crustaceans, worms, insects, frogs, and fish. It has a very slow metabolism and can sometimes go for weeks without eating. It lacks natural competitors. It is a long-lived species, with the captive record being an individual that lived in the Natura Artis Magistra, the Netherlands, for 52 years. In the wild, it may live for nearly 80 years. Lifecycle The Japanese giant salamander remains in bodies of water its entire life. During the mating season, typically in late August and early September, sexually mature males start actively finding suitable nesting sites and often migrate upstream into smaller sections of the river or its tributaries. Because of the limited availability of suitable nesting sites, only large and competitive males are able to occupy nesting sites and become den masters. A den master diligently cleans his den guards his den against intruders including other males who try to steal the den while allowing a sexually active female enter the den. Mating begins as the female starts laying eggs and the den master starts releasing sperm, which often stimulate other subordinate males hiding around the den to enter the den and join the mating. As a result, a single female often mates with multiple males. The den master stays in the den with the fertilized eggs while the other males and the female leave the den. He provides parental care for the embryos by guarding the eggs and fanning water over them with his tail to increase oxygen flow. The den-master continues providing parental care for the hatchlings until the following spring when the larvae start dispersing from the nest. Researchers also observed that den masters consumed eggs and larvae that showed the sign of failed fertilization, death, or water mold infection. The researchers termed the behavior of selectively eating his own eggs or larvae "hygienic filial cannibalism" and hypothesize that this behavior importantly increases the survivorship of the remaining offspring by preventing water mold infection on the dead offspring from spreading over the healthy offspring. Conservation Threats The Japanese giant salamander is threatened by pollution, habitat loss (among other changes, by the silting up of the rivers where it lives),