Egg Position and Weight of Hatchling Snapping Turtles, Chelydra serpentina, in Natural Nests

Based on laboratory experiments, Packard et al. (1980, 1981) reported that eggs of Chelydra serpentina exposed to substrate conditions similar to those encountered at the periphery of natural nests produce hatchlings having a living mass greater than hatchlings from eggs not contact with such a substrate. The differences weight were attributed to the absorbing of liquid water across the shell membrane during the first half of incubation by eggs contact with the substrate. Embryos within the eggs which absorb water use their energy reserves (yolk) more rapidly the formation of new tissues, resulting greater living weight of the hatchlings (Morris et al., 1983). This is of importance since large hatchlings are probably competitively superior to small hatchlings, growing more rapidly the period following hatching (Froese and Burghart, 1979) and have higher probabilities of survival (Swingland and Coe, 1979). Packard et al. (1980) also maintained that in the natural nests of numerous species of turtles, many (if not most) of the eggs are supported by contact with other eggs and do not contact the soil forming the walls of the nest cavity. If this is true, the advantage of substrate contact terms of increased hatchling weight must be numerically limited natural nests. If there is an adap-