Huddling And Torpor Flashcards
What are the only adult species of penguin that properly huddle?
Emperor penguins
What is torpor?
A state of reduced activity, metabolism and body temperature
It is short term
How is torpor distinguished from sleep?
The slow rate of arousal
What is hibernation?
A hypo-metabolic state that lasts weeks, maybe months
Why do animals that hibernate tend to be bigger?
Need sufficient stores
What are the levels of hypometabolism?
- Regional hypothermia
- Regulated central hypothermia
- Partial hibernation
- True hibernation
What are the 3 definitive and coordinated physiological changes that true hibernators undergo?
- Thermal dormancy
- Behavioural suppression
- Metabolic inhibition
What are the three most important environmental stimuli initiating hibernation?
Food supply
Day length
Ambient temperature
Why is arousal in hibernation energetically expensive?
Because it takes a lot of energy to raise the body temperature each time
What are the mechanisms of reheating?
Shivering
Increase activity
Non-shivering thermogenesis
What is non shivering thermogenesis?
Liver activity can increase to produce heat
Brown adipose tissue (mammals)
BMR can increase
How does brown adipose tissue differ from normal fat deposits?
Contains lipid droplets
Large numbers of mitochondria
A good blood supply
Innervation by the autonomic nervous system
What is hyperphagia? Bears undergo this
Eating more than they need during summer and autumn
What species of bear does hibernation occur?
Black bears- mainly males
