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/