Grizzly bears recycle waste to build muscle

During their months-long hibernation, grizzly bears perform an incredible feat: they recycle toxic urea, a waste product from protein breakdown, back into amino acids. This unique adaptation allows them to synthesize new proteins, preserving and even building muscle mass without eating. This process prevents muscle loss and kidney strain, ensuring bears emerge strong and ready for spring. Researchers believe understanding this could inspire new treatments for human muscle-wasting diseases.