Bats Upside Down Name: Drew H When bats sleep upside down does
all their blood rush to their heads like when people are hanging
upside down? Bats are so small that, unlike humans, the problem
of blood distribution is not a huge problem. They are able to
wrap themselves into a small package and like most mammals, they
can regulate blood flow by contracting their blood vessels to
direct and achieve blood flow. Up-dated July 2008 I concur with
the other answer here. I had noticed several sources on the
internet that describe "special valves" that keep blood from
pooling in the head (I was studying to co-lead a presentation on
bats), however none of my bat books describe this. In fact, the
book "Flying Foxes" by Leslie Hall (2001) states: "It was once
thought that bats had a series of valves in their blood vessels
which prevented blood rushing to their heads when they were
upside down. No such valves have been found and it is considered
that bat's small size and the small amount of blood allow them
to sleep upsid