Correlation Between the Number of Eggs Deposited in the Egg Sac and the Altitude of the Spawning Place in the Salamander Hynobius nigrescens

Abstract

The female of the salamander Hynobius nigrescens lays a pair of egg sacs in still water. In the breeding season of 1977, 1660 egg sacs of this species were collected from ponds of various altitudes scattered in Niigata Prefecture. The counting of the number of eggs deposited in one egg sac revealed that the number of eggs is decreases with the increase in altitude of the spawning place, e. g. the number was 65.1±13.9 (M±SD) at the Maze-ike, 20m above sea level, and 21.3±5.2 at the Chosuke-ike, 2000m above sea level, respectively.