They haven’t moved in a long time. Touch or light have no effect on them. Their hearts don’t seem to be beating. They haven’t taken a breath in a long time. Their skin is bone-chillingly cold and brittle to the touch. You probably don’t assume I’m talking about live beings based on that description. However, certain creatures can survive in this state due to a mechanism known as freeze tolerance.
Cold-blooded animals (ectotherms) are at the mercy of their environment, unlike mammals, whose bodies are constantly fighting to maintain a consistent temperature. As a result, when the temperature drops, they must devise a physiological strategy to endure the freezing winters.
The most commonly studied free
ze-tolerant animals are bugs and amphibians. Only a few frogs demonstrate a clear freeze-tolerance response among amphibians. To help them survive the winter, large amounts of their body fluid freeze into ice particles.
As the temperature drops, the physiological changes that prepare freeze-tolerant animals for cold weather begin, but they don’t happen overnight. Cryoprotectants are compounds that allow animals to get colder than freezing while protecting them from dehydration and other cell changes that might occur when ice forms. Depending on the species, the animals can tolerate temperatures ranging from 32 to -22 degrees F once frozen. Freeze tolerance can last anywhere from a few weeks to several months. Any frog who wishes to see the next summer must cycle through this procedure.
Thawing, on the other hand, may be just as vital as freezing. Freeze-tolerant animals are likely to go through numerous freeze-thaw cycles, during which their cryoprotectant distribution and cold tolerance improve. This shows that the cryoprotective mechanism does not end with the first freeze and continues as the winter gets colder. When spring approaches and the weather returns to typically above-freezing temperatures, the animals thaw out, their hearts begin to beat again, and they continue to live normally.
Scientists are interested in learning more about frost tolerance from
the animals who excel at it. Humans can’t freeze and thaw themselves, in case you didn’t know. Researchers can extend their findings to mammals by researching the physiological changes in freeze-tolerant organisms, such as conserving organs for later use and maintaining cell lines healthy while in storage. Scientists can learn more about functional difficulties in mammals by studying a “ideal” organism that has solved one. As a result, comparative physiologists continue to study the unique characteristics of other animals in order to learn how evolution has already dealt with these problems.
Graduated from ENSAT (national agronomic school of Toulouse) in plant sciences in 2018, I pursued a CIFRE doctorate under contract with Sun’Agri and INRAE in Avignon between 2019 and 2022. My thesis aimed to study dynamic agrivoltaic systems, in my case in arboriculture. I love to write and share science related Stuff Here on my Website. I am currently continuing at Sun’Agri as an R&D engineer.