Re: When bats hang upside down, does all their blood rush to their head?

Bats are mammals that frquently hang upside down.

Bird wings are powerful with supportive flight musculature. Since birds are upright unlike bats, they need lot of energy for "take-off" to fly against the gravity. Bats have evolved another simple way to conserve energy. They hang upside down in high ceilings. When they need to fly, just they drop down during which they fly - "take-off" while dropping down!

Giraffes have long neck and blood pumped by their heart should reach their brain travelling more against the gravity than other animals with a short neck. A long neck doesn't mean that only a small amount of blood reaches the brain!

Whether an animal has a long neck or a short neck; OR whether they are standing upright or hanging upside down the amount of blood reaching the brain will be the same. The circulatory system of these animals are suitably adapted for this purpose.

The hearts of bats and their blood vessels (suppling blood to brain) are modified for their upside down orientation, to avoid more amount of blood rushing to the brain.

References:

1. Biology of bats. Vol 1 (1970)
2. Biology of bats. Vol 2 (1970)
3. Biology of bats. Vol 3 (1977)
All the three volumes edited & published by:
W.A. Wimsatt, Academic Press, New York.