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The coincidence of hatching and emergence events with favorable conditions is crucial for turtle survival. Nocturnal emergence has been widely documented across marine and freshwater turtles, and has long been suggested as an adaptive behavior that reduces risks of heat stress and predation. To our knowledge, however, studies related to nocturnal emergence have mainly focused on the post‐hatching behaviors of turtles, and very few experimental studies have been performed to investigate the effects of hatching time on the distribution of emergence times over the course of a day. Here, we visually monitored the activity of the Chinese softshell turtle (Pelodiscus sinensis)—a shallow‐nesting freshwater turtle—from hatching to emergence. Our study provides evidence for the novel finding that (i) the timing of synchronous hatching events in P. sinensis coincides with the time of day when nest temperatures decrease, (ii) the synchrony between hatching and emergence may further facilitate their nocturnal emergence, and (iii) synchronous behaviors of hatchlings in the nest may be effective in reducing the risk of hatchling predation, and predation is more likely to occur in the asynchronous hatching groups. This study suggests that the hatching of shallow‐nesting P. sinensis in response to temperature changes in the nest might be an adaptive nocturnal emergence strategy. [ABSTRACT FROM AUTHOR]

The nesting activity of the Chinese softshell turtle (Pelodiscus sinensis) in its natural habitat is largely undocumented despite its broad geographical distribution across East Asia. Here, we report on female nesting behaviors, egg incubation, and hatchling emergence of P. sinensis on the Yellow River in northwestern China. In this region, the turtle is currently threatened by overharvesting, and successful conservation strategies should include strict monitoring of hunting and trade activities. [ABSTRACT FROM AUTHOR]

A detailed understanding of the spatial ecology and habitat requirements of endangered species is critical for population restoration and conservation. Home ranges and movements of the endangered Chinese softshell turtle (Pelodiscus sinensis) were investigated in the Yellow River, northwestern China, from October 2016 to July 2018. We monitored 9 adult turtles (5 females and 4 males) with radio transmitters. Mean linear range size was 440 ± 161 m SD, mean river channel area was 1.98 ± 0.72 ha SD, the average minimum convex polygon was 1.36 ± 0.65 ha SD, average 95% kernel density estimator measured 0.84 ± 0.51 ha SD, with a core area (50% kernel density estimator) of 0.30 ± 0.20 ha SD. Home range values were not significantly different between the sexes nor were they related to straight-line carapace length or mass. Daily movements of P. sinensis averaged 35 ± 18 m SD for males and 43 ± 18 m SD for females, and there was no significant difference between sexes or significant correlation between movement patterns and body size. However, during the nesting season, there was a significant difference between sexes. Turtle activity was highest in May (average daily movement 59 ± 6 m SD) and lowest in January (0.4 ± 0.6 m SD). Given that P. sinensis individuals have small home ranges and are capable of existing in small rivers, management efforts should protect smaller rivers that may be easily overlooked. Results from this study provide the first assessment of home range requirements for P. sinensis, which may be used in future population modeling efforts and are important for establishing conservation strategies for this vulnerable species. [ABSTRACT FROM AUTHOR]

The Chinese softshell turtle Pelodiscus sinensis, the most widely distributed endemic turtle in China, is mainly found in rivers, lakes, and ponds between N22.4-41.4° and E103.1-122.7°. However, this list excluded the Chinese softshell turtle and four other species of the same genus (Pelodiscus axenaria, Pelodiscus maackii, Pelodiscus parviformis and I Pelodiscus variegatus i ), which is a major impediment to establishing hunting regulations. [Extracted from the article]

Chinese soft-shelled turtle (Pelodiscus sinensis) hibernates without eating and drinking when the ambient temperature is very low. To better understand the characteristics of energy utilization during hibernation, the turtles in the physiological phases of summer active (SA), Pre-Hibernation (Pre-H), Mid-Hibernation (Mid-H) and early arousal (EA) were sampled. The results showed that the levels of serum triglyceride and hepatic lipid droplet were markedly increased in Pre-H and decreased in Mid-H compared with that in SA, indicating that P. sinensis experiences lipid accumulation in Pre-H and lipid is the predominant energy reserve during hibernation. The mRNA expression levels of genes (FABP and CPT-2) involved in lipolysis and lipid oxidation were up-regulated in Mid-H, while the genes related to lipid synthesis (FAS , ACSL-1 , ACC , elovl5 , and SCD1) were inhibited in Mid-H. Meanwhile, the mRNA expression levels of endoplasmic reticulum stress marker gene Bip and key genes (ATF4 , ATF6 , and IRE1α) involving the unfolded protein response were significantly increased in Mid-H and EA. Also, the expression levels of genes (ASK1 , JNK1 , and Bax) associated with cell apoptosis increased in Mid-H and EA, however, the expression of Bcl2 was inhibited in Mid-H. Therefore, hibernation can cause endoplasmic reticulum stress and apoptosis. The findings will provide a theoretical framework for an animal's cold adaptation and offer insights into preventing and managing metabolic syndrome. Changes of hetapic lipid metabolism in different physiological periods and their physiological regulatory mechanisms in P. sinensis. By Figdraw. [Display omitted] • Chinese soft-shelled turtle (Pelodiscus sinensis) is used as a natural model of obesity tolerance due to lipid accumulation before hibernation. • Lipid oxidation increased while lipid synthesis inhibited during the turtles' hibernation. • Lipid accumulation in the liver of the Chinese soft-shelled turtle (Pelodiscus sinensis) activated endoplasmic reticulum stress and caused cell apoptosis [ABSTRACT FROM AUTHOR]