23% of the combined weight of all food items. It has very poor eyesight, so it depends on special sensory nodes that run in a line on the body from head to tail. It is capable of sensing the slightest vibrations around it with the help of these nodes. Based on a captive study, most activity is from the earlier evening to the early night. Most individuals stop feeding at water temperatures above and feeding ceases almost entirely at . Temperatures of are lethal to Chinese giant salamanders. Breeding and lifecycle Both sexes maintain a territory, averaging for males and for females. The reproductive cycle is initiated when the water temperature reaches and mating occurs between July and September. The female lays 400–500 eggs in an underwater breeding cavity, which is guarded by the male until the eggs hatch after 50–60 days. They have a variety of different courtship displays including knocking bellies, leaning side-to-side, riding, mouth-to-mouth posturing, chasing, rolling over, inviting, and cohabiting. When laid, the eggs measure in diameter, but they increase to about double that size by absorbing water. When hatching, the larvae are about long and external gills remain until a length of about at an age of 3 years.The external gills start to slowly decrease in size around 9 to 16 months, the rate of this phenomenon occurs in relation to the rate of disovled oxygen, breeding density, water temperatures, and individual differences. Maturity is reached at an age of 5 to 6 years and a length of . The maximum age reached by Chinese giant salamanders is unknown, but it is at least 60 years based on captive individuals. Undocumented claims have been made of 200-year-old Chinese giant salamanders, but these are considered unreliable. Distribution and habitat The Chinese giant salamander species complex comprises five clades, with multiple possibly worthy of species recognition. Their native ranges differ, but release of Chinese giant salamanders from captivity has complicated this picture. They were widespread in central, south-western and southern China, although their range is now highly fragmented. Their range spans the area from Qinghai east to Jiangsu and south to Sichuan, Guangxi and Guangdong; notably in the basins of the Yangtze, Yellow and Pearl Rivers. One is from the Pearl River basin (at least in Guangxi), two from the Yellow River basin, one from the Yangtze River basin (at least in Chongqing and Guizhou) and the