Archive
BAT RESEARCH - HIBERNATION
04/12/2024
Have you ever wondered how bats (and other hibernating mammals) keep their blood circulating when they are in a state of cold torpor during hibernation? Perhaps some of you have, and it is a question recently considered in more detail by scientists as greater knowledge may lead to innovations and better treatments regarding states of torpor in human medicine.
A research team at the University of Greifswald in Germany have investigated this fascinating area of biology[1], specifically the thermomechanical properties of blood in hibernation. Various mammals hibernate (slowing their heart rate and reducing body temperature) to save energy in winter in colder climates when food is scarce. This includes some but not all bats.
[1] https://pubmed.ncbi.nlm.nih.gov/39401351/
The two species studied in this research were the common noctule Nyctalus noctula (Schreber, 1774), a hibernating bat species, and the Egyptian fruit bat Rousettus aegyptiacus (Geoffroy, 1810) which does not hibernate. The investigations had a focus on red blood cells in the bats as well as in humans because they are of primary importance in maintaining healthy metabolism, especially in distributing oxygen throughout the body.
The results are fascinating. It transpires that all the red blood cells from humans and both bat species display reduced elasticity and become stickier (more viscous) when temperatures are reduced from 37°C to 23°C. However, when they are cooled further, to 10°C, only the bat cells continued the changes in these thermomechanical changes. Both bat species displayed the changes even though the fruit bats don’t hibernate, presumably because the trait is genetically retained in the Chiroptera, although that would need more research.
The advantage of the changes to red blood cells in cold temperatures is that they can then move more slowly along the capillaries which allows more time for gas exchange to maintain a healthy circulation during torpor in hibernation. The researchers note that this may have advantages if such changes could be initiated in humans, for example in establishing a synthetic torpor safely in medicine and space flight.
Betts Ecology carry out bat surveys and related work under licence throughout the year, so all new research is of great interest.
