Most bats infected with rabies become paralyzed and fall to the ground, and rabies transmission is usually only a problem if a human picks up a sick bat. Colonies that roost in attics can cause the owners of the house to spend unnecessary money on cleaning. The presence of bats may also lower the resale value of buildings. They have possibly become more abundant with the growth of human populations because of desirable manmade roosting areas such as attics, caves and mines. It doesn't do well in captivity unless kept at very high temperatures.
Males live longer than females.
There may be an evolutionary trend toward loss of upper premolars in Myotis lucifugus . References Barbour, R. W., and Davis, W. H. Bats of America. The University Press of Kentucky. Griffin, D. R. Listening int he Dark. New Haven, Connecticut.