Alaskan wood frogs can go eight months without peeing by turning their own waste into a life-saving shield.

The wood frog, known as Lithobates sylvaticus, has mastered a trick called freeze tolerance. When the weather gets cold, its liver floods its body with sugar and a waste product called urea. Normally, animals must pee out urea because it is toxic. But for these frogs, it acts like a thick syrup that keeps their cells from bursting when they turn into little frog-shaped ice cubes.Researchers like Jon Costanzo from Miami University found that these frogs can stay frozen for up to 218 days. During this long winter nap, the frog's heart stops beating and it stops breathing entirely. It can survive temperatures as low as 0 degrees Fahrenheit because the urea and sugar protect its delicate insides from sharp ice crystals.Tiny microbes in the frog's gut also help out by breaking down the urea into nitrogen. This gives the frog a way to recycle nutrients since it cannot eat or drink while frozen under the snow. When spring finally arrives, the frog thaws from the inside out. Its heart starts beating again within just a few hours, and it hops away to find a snack and finally use the bathroom.