winter up north. Monarchs are sheltered on their winter grounds
in the mountain Oyamel fir forests in Mexico. The trees and altitude
keep the habitat warm enough so monarchs won't freeze, but cool
enough to help them save energy.
Why do you think monarchs leave these winter sanctuaries
and migrate north each spring?
They are born with the urge and ability to migrate north. Scientists
think the geography of our hemisphere has a lot to
do with why this instinct developed.