* Thick fur or blubber: These provide insulation to help animals stay warm in freezing temperatures. Rainforests are hot and humid, so this type of insulation would be unnecessary and even detrimental.
* White fur or feathers: This helps animals camouflage themselves against the snow and ice. Rainforests have a lot of greenery, so white would actually make an animal more visible.
* Hibernation: Many animals in cold climates hibernate during the winter to conserve energy when food is scarce. Rainforests don't have a distinct winter period with a lack of food.
* Migration: Some animals migrate to warmer areas during the winter. Rainforests are already warm, so migration for this reason would be less common.
* Anti-freeze compounds: Some animals have evolved special chemicals in their blood that prevent freezing. Rainforests are not cold enough for this adaptation to be necessary.
Let me know if you would like more examples!
