Bats! 

Though we have seen these bat many times, it wasn't until the past year we were able to examine them up close. On several recent occasions we came across these bats just hanging out in natural and man made caves in Massachusetts.  Though most fear being bitten by bats, they seemed very acquiescent  when they were gently touched. Unlike most believe, bats do not attack humans. Also only one percent of bats carry rabies and those who do, die very quickly. Just to be safe we were wearing gloves when petting these winged hamsters.

There are 3 types of bats in New England, little brown myotis which are 3 1/2" long with a wing span of 9". and the big brown bats and eastern red bats that are 4 1/2" long with a wing span of 12". 

I'm not a bat expert but I would guess that in the photo, the Bat on the left is an eastern red and the one on the right is a little brown myotis.