Playing Dead, Saving Lives

When the going gets tough, the tough play dead. That's the motto of two of nature's most durable creatures—the resurrection plant and the water bear. Together, their amazing biochemical tricks may show scientists how to save millions of lives in the developing world.

Resurrection plants refer to a group of desert mosses that shrivel up during dry spells and appear dead for years, or even decades. But once it rains, the plants become lush and green again, as if nothing happened. The water bear has a similar trick for playing dead. The microscopic animal can essentially shut down and, during that time, endure some of the most brutal environments known to man. It can survive temperatures near absolute zero and above 300°F, go a decade without water, withstand 1,000 times more radiation than any other animal on Earth, and even stay alive in the vacuum of space. Under normal circumstances, the water bear looks like a sleeping bag with chubby legs, but when it encounters extreme conditions, the bag shrivels up. If conditions go back to normal, the little fellow only needs a little water to become itself again.

The secret to the survival of both organisms is intense hibernation. They replace all of the water in their bodies with a sugar that hardens into glass. The result is a state of suspended animation. And while the process won't work to preserve people (replacing the water in our blood with sugar would kill us), it does work to preserve vaccines.

The World Health Organization estimates that 2 million children die each year from vaccine-preventable diseases such as diphtheria, tetanus, and whooping cough. Because vaccines hold living materials that die quickly in tropical heat, transporting them safely to those in need can be difficult. That's why a British company has taken a page from water bears and resurrection plants. They've created a sugar preservative that hardens the living material inside vaccines into microscopic glass beads, allowing the vaccines to last for more than a week in sweltering climates.