Hibernation is a natural behavior that allows animals to survive the winter by slowing down their metabolism and body temperature. Hibernating animals use stored fat for energy while they are inactive. 

Aestivation is a state of dormancy that animals enter during hot and dry periods to conserve energy and avoid dehydration. It's similar to hibernation, but occurs in the summer instead of winter. 

Counter-shading is a camouflage technique where an animal's upper body is darker and its lower body is lighter. It is an adaptive feature that enables animals to remain undetected or unnoticed.

Animal migration is when animals move from one place to another in a regular pattern. Migrations can be seasonal, but other factors like rainfall can also influence them.