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HIBERNATION AND MIGRATION
October 16 and 19
Hibernation
Definition- A condition in which an animal remains in a sleep-like state for weeks, months, or even years.
Examples Black bears fatten themselves up during the
summer when food is plentiful. During winter, they hibernate and slowly use up the food energy stored in their fat.
Some insects and reptiles also hibernate when temperatures are low and food and water are scarce.
Hibernation Triggers
Cold temperatures There are other factors that can trigger
hibernation, but cold temperatures is the main one we will focus on.
Hibernating Animals
Most animals that hibernate are smaller mammals because large mammals require excessive energy to emerge from hibernation.
Some hibernating rodents are not able to store adequate energy in fat reserves to last them through winter so they store extra food in their burrows so they can refuel during periodic arousals from hibernation.
During Hibernation
Metabolism decreases Metabolism- refer to all chemical reactions that occur in
living organisms, including digestion and the transport of substances into and between different cells.
Can still hear
Brains are tuned into changes of external stimuli such as temperature, light, and sound because they can mean danger. For instance, a drop in temperature could be dangerous
because the animal’s body temperature could drop too low and they could freeze to death.
Arousal from Hibernation
Body temperature will increase when they wake.
If the outside temperature dropped below 0⁰ C it would trigger arousal so that the animal did not freeze to death.
Dangerous for an animal to arise from hibernation when the ground is still covered in snow because they may not be able to find food.
Torpor
Definition- A short-term reduction of body temperature and metabolic rate on cold days.
Short, minimized version of hibernation.
Organisms vital functions decrease to help them conserve energy.
Some species will go into daily torpor to conserve energy for hunting at night. Example: Nighthawk
Triggered by shortage of food or cold temperatures.
Estivation
Helps animals survive hot, dry weather.
Triggered by hot temperatures or lack of water.
Example: A lizard burrowing underground during summer to keep cool.
Migration
Definition- A seasonal movement of animals from one region to another.
Examples Birds moving to areas where they can find
food during the cold and dry months. Some species migrate for the purpose of
mating and giving birth. During the dry season, elephants travel long
distances to reach rivers and other water sources.
Migration Triggers and Preparation
Animals typically prepare for migration by storing extra fat.
Migration triggers Hormones Change in daylength
Migration Skills
Magnetite in their brains
Using the stars to navigate
Using coastlines to navigate
Migrating animals will travel great distances to survive.
BrainPOP videos
https://www.brainpop.com/science/ecologyandbehavior/hibernation/
https://www.brainpop.com/science/ecologyandbehavior/migration/