How tiny Antarctic creatures hold clues to medical and scientific breakthroughs

Nottingham: In Antarctica’s freezing depths, tiny creatures have mastered survival tactics that could unlock secrets to extreme cold resistance, with implications for science and medicine.

Some of the most intense battles against the environment are waged by the smallest of creatures.

When it’s cold, we, as warm-blooded (endothermic), animals simply put on a coat. Other endotherms, can be large, fat or furry to insulate their body from the cold.

Generating your own body heat, however, requires a lot of energy. Insects do not do not do this. The heat they need for metabolism and growth comes from the environment. This is partly how they are so abundant around the world. They need less energy to grow compared with warm-blooded animals like mammals and are great at exploiting this advantage.

Not being able to generate your own body heat is a problem for insects in cold places. They are at the mercy of the environmental temperature and can only grow, develop and feed when it is warm enough. Typically this optimum temperature is around 20 degrees Celsius.

Yet some insects survive when temperatures drop below freezing. Generally, when the temperature goes below 0°C this causes damage to animal cells and even death. This cell damage is what causes frostbite.

Many insects use one of two simple strategies. Freeze tolerance or freeze avoidance.

For example, they produce cryoprotectants, such as glycerol, which lower their freezing point. This allows the animal to undergo supercooling without freezing. Some generate antifreeze proteins that stop ice crystals from forming in their tissue.

Mites are common in the Antarctic – there are hundreds of species. Some even live in the nasal cavities of penguins. Penguin noses provide not only a source of food for the mites that feed on the penguins’ dead skin cells, but also a warm environment.

However, some Antarctic mites, which don’t rely on a host, such as Halozetes belgicae, are freeze-avoiding, using antifreeze compounds to lower the freezing point of their body to well below 0 degrees Celsius.

One of the smallest land animals in Antarctica are the springtails, related to primitive insects but lacking some of the features we see in modern insects.

Springtails like *Gomphiocephalus hodgsoni* survive Antarctic cold by avoiding freezing until -38°C. *Belgica Antarctica*, the only true insect there, tolerates ice inside its body and dehydrates to prevent damage.

Nematodes and tardigrades also survive freezing through cryptobiosis. These adaptations could inform advances in cryopreservation, organ transplants, food storage, and climate resilience.