North Queensland Naturalist

Abstract

I report data on clutch size, nest size, the times taken to complete nesting stages and a description of nesting behaviours of 17 wild Johnstone River Snapping Turtles Elseya sp. based on observations spanning ten years. Clutch size ranged from 3 to 15 eggs, the nest opening was essentially circular (60 mm diameter), vertical nest depths ranged from 100 to 210 mm, egg laying times from 3 to 17 minutes, and nest filling-in times from 13 to 48 minutes. Excavation times were always the longest stage of the nesting process (> 1 hr), although few complete times were obtained. There was no relationship between clutch size and either egg-laying times nor nest filling-in times.
A few nesting females used their knees (as well as the feet) to compact soil (n = 4) and also the plastron to flatten the soil surface during the filling in of nests (n = 3). Eggs with impact fractures were uncommon (6% of clutches) and in nearly all instances fractures were due to embedded stones in the wall of the egg chamber. I observed two instances where the entire nesting process was completed, including back-filling the nest, yet no eggs were laid.