Animals at the extremes: hibernation and torpor

Hibernation is an ingenious adaptation that some animals employ to survive difficult conditions in winter. This free course, Animals at the extremes: hibernation and torpor, examines the differences between hibernation and torpor, and discusses the characteristic signs of hibernation behaviour. It explores the triggers that bring on hibernation, and whether internal signals or external season cues are predominant. It also examines the physiological adaptations that occur in hibernating animals.

• Introduction
• Learning outcomes
• 1 Hibernation and torpor: An introduction
• 1 Hibernation and torpor: An introduction
• 2 The nature and extent of hibernation and torpor in endotherms
• 2 The nature and extent of hibernation and torpor in endotherms
• 2.1 Degrees of torpor
• 2.2 Species showing torpor or deep hibernation
• 2.3 Hibernators as eutherms
• 2.4 Summary
• 3 Characteristics of hibernation behaviour
• 3 Characteristics of hibernation behaviour
• 3.1 Introduction
• 3.1 Signals for entry
• 3.2 Physiological changes during entry
• 3.3 Maintenance
• 3.4 Arousal
• 3.4.1 Alarm arousal
• 3.4.2 Periodic arousal
• 3.5 Arousal (continued)
• 3.5.1 Final arousal
• 3.6 Length of torpor bouts in hibernation
• 3.7 Summary
• 4 Physiological adaptations – molecules and cells
• 4 Physiological adaptations – molecules and cells
• 4.1 Scientific approaches
• 4.2 Arresting protein synthesis
• 4.3 Cellular changes
• 4.4 Cell survival mechanisms
• 4.5 Summary
• 5 Physiological adaptations – respiration and energy provision
• 5 Physiological adaptations – respiration and energy provision
• 5.1 Introduction
• 5.2 Energy sources in torpor and hibernation
• 5.3 Mitochondrial adaptations
• 5.4 Inspiratory drive
• 5.5 Energy budgeting – the benefits of hibernation and torpor
• 5.6 The importance of size and habitat
• 5.7 Summary
• 6 Control systems
• 6 Control systems
• 6.1 Introduction
• 6.2 The hypothalamus as central regulator
• 6.3 Metabolic regulation and the midbrain
• 6.4 Rapid-response genes and rhythmic neuronal activity
• 6.5 The neurotransmitters histamine and serotonin: a role for chemical signalling between neurons of the hypothalamus
• 6.6 Hormones and hibernation
• 6.6.1 Melatonin
• 6.6.2 Hibernation-induction trigger
• 6.7 Sleep, the brain and hibernation
• 6.8 Summary
• Course Questions
• Conclusion
• References
• Further reading
• Acknowledgements