We Thought We Knew Turtles: A New Discovery Raises a Mystery

Introduction

• A recent discovery about turtles has unveiled new behaviors, challenging previous assumptions about these reptiles.
• The study highlights nocturnal basking in freshwater turtles, which could have implications for understanding their response to climate change.

Discovery of Nocturnal Basking

• Location: Ross River, Townsville, Australia.
• Researchers Involved: Eric Nordberg (University of New England) and Don McKnight (La Trobe University).
• Initial Observation (2017): Krefft’s river turtles were seen basking in moonlight, which was previously undocumented.
• Subsequent Research: Led to a paper published in Global Ecology and Conservation.

Global Survey

• Study Launch (2019): Global call for data collection on nocturnal basking.
• Data Collected: Nearly 900,000 photos, 29 species, 7 of 11 freshwater turtle families.
• Findings: 13 species across 6 families exhibited night basking, with longer durations compared to daytime basking.

Investigating the Phenomenon

• Hypotheses Tested:
  • Ruled out moon phase, winds, predator avoidance (seen basking near crocodiles).
• Geographical Variations: More common in tropical/subtropical areas, closer to the Equator.

Thermoregulation Study

• Researcher: Rosie Kidman, James Cook University.
• Method: Laboratory study of 25 Krefft’s river turtles regarding temperature preferences.
• Findings: Turtles basked more at night when water temperatures were higher, suggesting nocturnal basking helps cool off.

Implications for Climate Change

• Global Warming Predictions: Temperatures could rise by 2.7°F by 2030.
• Potential Impact: Night basking might help turtles avoid heat stress.
• Conservation Concerns:
  • 60% of freshwater turtle/tortoise species are threatened or extinct.
  • Rising temperatures could affect heat-sensitive ectotherms like turtles.

Conclusion

• The study underscores the importance of continuous research on well-known species to uncover unknown behaviors and adapt conservation strategies accordingly.
• Nocturnal basking adds a new dimension to understanding turtle ecology and their adaptability to changing climates.