Shedding of the skin is necessary to provide for growth and wear in snakes. The milkiness or bluing of the eyes, which causes partial blindness, marks the initial stage of shedding and is caused by a discharge of the exuvial glands that loosens the old _stratum corneum_ from the layer below. In four to seven days the opaqueness disappears, and the snake sheds after an additional three to six days (Table 12). Young snakes first shed within a few days after birth and generally shed more frequently than adults, but the interval is variable. The eyes of three young cottonmouths observed by Wharton (1960:126) became milky on the fourth day but cleared on the seventh day, and the skin was shed on the eighth day. The eyes of three young kept by me became milky two to three days after birth, cleared on the seventh to tenth days, and the skin was shed on the thirteenth day. Possibly the relatively long interval in this instance resulted from low relative humidity in the room where the snakes were kept. According to Fitch (1960:134), litters of young copperheads usually shed within three to ten days after birth; but under unusually dry conditions shedding did not occur for several weeks. TABLE 12.--Duration of Preparatory Period (in days) to Shedding in 11 Cottonmouths. ============================== |Duration | Time |Time from | | of |between |beginning | |cloudiness|clearing| of | | | and |cloudiness| |of eyes |shedding| until | | | | shedding | |----------+--------+----------| | 5 | 6 | 11 | | 7 | 3 | 10 | | - | - | 6 | | - | - | 6 | | 5 | 3 | 8 | | 4 | 6 | 10 | | 7 | 3 | 10 | | 5 | 6 | 11 | | 5 | 3 | 8 | | 7 | - | - | | 7 | 3 | 10 | | ---- | ----| ---- | |[=X] 5.4 |[=X] 3.8| [=X] 9.0 | ------------------------------