It sounds like something straight out of science fiction, but some animals can actually freeze solid and live to tell the tale. These remarkable creatures have evolved ways to endure temperatures that would normally be fatal, essentially pressing pause on life until conditions improve.
From tiny insects to amphibians that thaw out with the spring, their survival strategies are nothing short of biological marvels. Scientists studying these animals are uncovering secrets that could one day influence medical science, space exploration, and cryogenics.
This article is for general knowledge only and is based on information from online sources. Photos are for illustrative purposes only.
Wood Frog
North American wood frogs practically become frog-shaped ice cubes each winter. Their hearts stop beating, blood stops flowing, and up to 70 percent of the water in their bodies turns to ice. The secret lies in glucose, which floods their cells like natural antifreeze.
This sugar prevents ice crystals from damaging delicate cell structures. When spring arrives and temperatures rise, these frogs thaw out gradually. Within hours, their hearts resume pumping and they hop away to find mates, as if nothing unusual happened at all.
Arctic Ground Squirrel
Living in Alaska and northern Canada means dealing with brutal cold, and Arctic ground squirrels have adapted remarkably. During hibernation, their body temperature drops below freezing, reaching as low as minus two degrees Celsius. Blood supercools without actually freezing solid, which protects vital organs.
Every few weeks, they briefly warm up to restore normal body functions before cooling down again. This cycle continues throughout winter. Males emerge first in spring, followed by females ready to breed and raise young during the short Arctic summer.
Woolly Bear Caterpillar
Arctic woolly bear caterpillars take freeze tolerance to extreme levels. These fuzzy creatures can survive temperatures dropping to minus 70 degrees Celsius. Their development takes up to 14 years because growing seasons in the High Arctic last only a few weeks annually.
Each autumn, they produce cryoprotective chemicals that prevent ice damage. Most of each year gets spent frozen solid under snow. When brief summer arrives, they thaw, eat voraciously, then freeze again. Eventually, they pupate and emerge as rather unremarkable moths.
Painted Turtle Hatchlings
Baby painted turtles face a risky situation when they hatch late in autumn. Too small to dig deep enough to escape freezing temperatures, they remain in shallow nests through winter. Ice forms in their body cavities and between organs, yet they survive.
Unlike adults who overwinter underwater, hatchlings rely on specialized proteins and glucose to protect cells from ice damage. Their shells actually help by limiting how much ice forms inside. Come spring, these tiny turtles thaw and dig their way to the surface, ready to start life.
Tardigrades
Tardigrades, nicknamed water bears, might be the toughest animals on Earth. These microscopic creatures survive being frozen at temperatures near absolute zero. They enter a state called cryptobiosis, essentially shutting down all metabolic processes.
Water gets replaced with protective sugars, and their bodies shrivel into a dried husk called a tun. In this state, they can endure extreme radiation, crushing pressure, and even the vacuum of space. Add water, and they rehydrate within hours, resuming normal activities as if nothing happened.
Spring Peeper Frog
These tiny frogs, barely larger than a thumbnail, belt out surprisingly loud mating calls each spring. Before that musical performance, they endure harsh winters frozen beneath leaf litter. Ice forms outside their cells while glucose and urea act as internal antifreeze.
Their breathing and heartbeat cease completely during frozen periods. Spring peepers can survive multiple freeze-thaw cycles throughout winter. When temperatures stabilize above freezing, they thaw rapidly and head to vernal pools. Their cheerful peeping signals that winter has finally lost its grip.
