Big brown bats often hibernate within less than 80 kilometers of their summer roosts.
That short seasonal movement reflects the species’ generally sedentary lifestyle. Rather than undertaking the long migrations made by some tree-roosting bats, big brown bats commonly winter in nearby caves, mines, buildings, storm sewers, or rock crevices.
They usually enter hibernation around November and may roost alone or in small groups. Their winter sites are often cooler and drier than those preferred by little brown bats, and individuals may briefly arouse to move, drink, or respond to changing conditions.
The distance is a general rule, not a hard biological boundary. Some big brown bats travel farther, and regional studies have reported movements approaching or exceeding 80 kilometers. The quiz’s wording—“often” and “less than”—matches the commonly cited pattern, while 500 and 200 kilometers describe much longer movements associated with more migratory bat species.