Hibernation Flashcards
Define hibernation
the condition/ period of an animal or plant in a dormant state in order to survive against climate conditions
What is summer hibernation known as?
Estivation
What is estivation?
Summer hibernation
What are 3 factors that can trigger hibernation?
Photoperiod - day light length
Temperature
Shortage of food
Define torpid
Mental and physical inactivity
What is the difference between carnivores and rodents in hibernation?
Carnivores are like sleepers and can wake more easily.
Rodents are deep sleepers that go into a coma-like state of torpidity
What is the difference between endothermic and ectothermic hibernation?
Ectothermic hibernation is UNCONTROLLED, forced by environmental conditions.
Endothermic is CONTROLLED - can delay going into hibernation until fully prepared
Why are smaller species more prone to heat loss than larger species?
Because smaller species have a greater surface area to volume ratio
Why would an animal go into estivation?
To avoid hot and dry conditions for protection
Name 1 animal that estivates
Fat-tailed lemur
Kangaroo rat
Desert Tortoise
What is hibernacula?
Den/ shelter preparation for hibernation
Which type of ‘therm’ is more likely to suspend hibernation until fully prepared and why?
Endotherms
Because their hibernation is more controlled, whereas ectotherms are more controlled by environmental conditions
Which hormone does the pineal gland secrete for hibernation and what triggers it?
Melatonin
Triggered by lower levels of sunlight (photoperiod)
What happens to the thyroid regulation in hibernation?
Thyroid shrinks the metabolic rate, reduces secretion, regulates the amount of sugar needed by the animal
Name 3 things the pituitary gland does to the body during hibernation?
Deposits fat Lowers body temp Slows heart rate Slows respiration Triggers insulin release
How much does the Basal Metabolic Rate (BMR) drop to in hibernation?
Below 5%
How much can heart rate drop to in hibernation?
To as little as 2.5% of usual level
Give an example of high rate decrease in a species in hibernation
Either:
Chipmunks - slows from 200bpm to 5bpm
Hedgehogs - slows from 188bpm to 21bpm
How much does an animals breathing rate decrease by in hibernation?
Drops by 50%-100%
some animals stop breathing althogether
What is apnea?
Several minutes of ceased breathing
What is the sole energy of species in hibernation?
Fat
Why do animals go to hibernation on an empty stomach?
Because digestion stops so food wouldn’t be digested and instead would rot
How does the wood frog prevent freezing in hibernation?
The liver produces lots of glucose to prop up cells and prevent them from being lysed (bursting)
What is the average hibernation length in the artic circle vs north temperate regions
Artic Circle = 9 month average
North Temperate Regions = 6 month average
Why might a species periodically arouse during hibernation?
To avoid nerve damage To avoid completely freezing To boost the immune system To recover from stress of metabolic depression To get rid of waste If triggered by a threat
What triggers the end of hibernation?
Temperature
Photoperiod (longer daylight hours)
Biological rhythms
