Giraffes can go without sleep for weeks, while brown bats sleep for nearly the entire day. The golden dormouse carefully balances itself on the branch of a tree to sleep, and any quiver of the twig wakes it up immediately.
From the miniscule tree shrew to the most physically imposing of mammals, animals have varying sleep patterns and habits. Rats have similar sleep needs to humans, requiring rest to become alert and learn new tasks for the upcoming day. Certain canines have even helped scientists in treating serious sleep disorders.