Studying Hibernating Frogs
I found this interesting, because as a child I used to be fascinated by frogs. Growing up on the Gulf Coast, there were many swamps, bayous, canals, etc., perfect habitat for frogs. We’d play with schools of tadpoles and always too kthem to school for show and tell. Of course, as they matured and hopped out, every year my grandparent’s yard was covered with miniature baby frogs. They were only half- to a full inch long and so crazy cute. My family would watch thousands of them hopping all over the grass and I’d play with them and marvel to see them cling to everything in sight.
Also, this reminds me of the interesting tales of revived frogs from ancient times. In many mines they have found frogs encased in coal or rocks that revived and hopped out when the rocks were split. I wonder how long a frog in hibernation can actually last? Hundreds… thousands of years? Who knows. It’d be a genetic treasure to find some very ancient preserved frogs.
Obesity Clues From Research On How Burrowing Frogs Survive Years Without Food
Many species of animals go through a period of torpor to conserve energy when resources are scarce. But when it comes to switching to energy-saving mode, the champion by far among vertebrates is the burrowing frog (Cyclorana alboguttata), which can survive for several years buried in the mud in the absence of any food or water.
How do they accomplish this feat? A team of scientists at the University of Queensland have discovered that the metabolism of their cells changes radically during the dormancy period allowing the frogs to maximise the use of their limited energy resources without ever running on empty.
This discovery could prove to have important medical applications in the long term. “It could potentially be useful in the treatment of energy-related disorders such as obesity”, explains Ms. Sara Kayes who will present her findings at the Society of Experimental Biology Annual Meeting in Glasgow on the 29th June 2009.
When the operation efficiency of the mitochondria, the tiny “power plants” of the cell, was measured during the dormancy period, it was found to be significantly higher compared to that observed in active animals. This trick , known as mitochondrial coupling, allows these frogs to be extremely efficient in the use of the limited energy stores they have by increasing the total amount of energy obtained per unit consumed, allowing them to easily outperform other species whose energy production efficiency remains essentially the same even when they happen to be inactive for extended periods.
If this is such an efficient way to use energy resources during dormancy, how come that it is not more widespread in the animal kingdom? The researchers speculate that a potential drawback may be the increased production of reactive oxygen species, which may in turn lead to oxidative stress. Since these small molecules are believed to cause most of the damage during periods of re-awakening, increasing mitochondrial coupling does not seem to be a particularly good idea for animals that tend to exhibit short periods of spontaneous arousal during the dormancy period, in some cases even daily.
Burrowing frogs, on the other hand, are believed to remain deeply asleep during the entire period of dormancy. Furthermore, being cold-blooded, they don’t have the need to maintain a basal level of heat production, minimizing their energy needs.