Clusters may consist of hundreds of bats per square foot. A few species reside in caves year-round, although they usually use different caves in summer than winter. Most cave bats return year after year to the same caves. Tree bats seldom enter caves. They roost in trees during summer days and spend winter primarily in hollow trees.
Several species make long migration flights.
The first crossword puzzle was printed in the Sunday New York World on Dec. 21, 1913.