Bear hibernation is very different from most hibernating mammals. They don’t awaken and feed at any time during their hibernation. They seem to shut down many of their biological systems almost entirely. This shut-down includes their kidneys.
Once bears hibernate, they cease to urinate. The blood supply to the kidneys is greatly reduced, and almost all fluid movement in the kidneys stops. Under most conditions, such a stoppage would cause damage to the kidneys and produce toxic conditions in the body. Amazingly, none of this happens. Tests show no measurable changes in the chemical make-up of the blood and no accumulation of waste products.
What a great advantage this shut-down is to the bear. Not only does it rest the kidneys and conserve energy consumption in the bear’s body, but it also eliminates dehydration. If the bear released water and did not replace it, the bear would eventually die. In the deep sleep of hibernation, there is no way to replace the water.
Bear hibernation is a very complex way of conserving energy, protecting the bear, and protecting the bear’s potential food from over-consumption. The design of such a system shows incredible wisdom and design by a Master Designer.
© Roland Earnst