Hibernation
When an animal sleeps all winter long
it is called hibernation.
Links
http://www.buzzle.com/articles/hibernating-animals-list.html
http://www.buzzle.com/articles/animals-that-hibernate.html
http://www.enchantedlearning.com/painting/Hibernate.shtml
http://teacher.scholastic.com/products/instructor/timetosleep.htm
http://library.thinkquest.org/TQ0312800/hibernate.htm
http://www.ehow.com/info_8088159_list-animals-hibernate.html
http://www.mrsjonesroom.com/themes/hibernation.html
http://www.atozkidsstuff.com/hibernation.html
http://oblockbooksblog.wordpress.com/2012/01/20/free-hibernation-activities/