From 2000 to 2002, the reproductive ecology of the endangered Hainan four eye-spotted turtle (Sacalia insulensis) was studied on Hainan Island, China. A total of 147 adult females were captured, and their reproductive status was evaluated by palpation, X-ray imaging, and ultrasound. Twenty-two gravid females were under observation when they laid their eggs. We observed gravid females and nesting behavior along stream banks between December and April. Nest dimensions ranged from 5 to 6 cm in diameter and from 2 to 3 cm in depth. No females in our study produced more than 1 clutch per season. Clutch size average was 1.9 eggs (range = 1–3 eggs, SD = 0.56, n = 22) with an average egg mass of 16.05 g (range = 11.8–21.0 g, SD = 2.417, n = 21), an average egg width of 2.36 cm (range = 2.1–2.7 cm, SD = 0.135, n = 21), and an average length of 4.65 cm (range = 3.9–5.3 cm, SD = 0.400, n = 21). Hatching success rate was 53%, and hatchlings emerged after an average of 120.9 d (range = 98–148 d, SD = 14.94, n = 21) in late June to early July. The mean nesting site ground temperature was 24.43°C (range = 15.0°C–30.2°C, SD = 2.712, n = 7).
Bibliographical noteThe present study was supported by the National Natural Science Foundation of China (No. 31772486 to H.S. and No. 31860608 to J.W.). The methods of this study were approved by the Animal Research Ethics Committee of Hainan Provincial Education Centre for Ecology and Environment, Hainan Normal University (HNECEE-2007-002), and were carried out in strict accordance with the institutional guidelines. We thank Hainan Medical University for assistance in X-ray imaging and ultrasound scanning. We thank Y.L. Fu, B.L. Fu, and many undergraduate students for their assistance during the fieldwork. We are grateful to J.R. Buskirk and K.H. Kikillus for providing constructive comments on a previous version of the manuscript. We thank 2 anonymous reviewers for providing constructive comments on this manuscript.
- Sacalia insulensis
- radio tracking
- nesting behavior
- Sacalia quadriocellata