The Resilient Brain of the Arctic Ground Squirrel

As a hibernating animal begins its sleep, its body temperature cools. How low can it go? A dozen arctic ground squirrels appear to have set a record—when their body temperature dropped to 26.8 degrees Fahrenheit (-2.9°C)! At that temperature, we would expect their brains to freeze. How does the arctic ground squirrel survive?

Consider: Every two or three weeks during hibernation, the arctic ground squirrel shivers itself back to its normal body temperature of 97.5 degrees Fahrenheit (36.4°C) and does not get cold again for some 12 to 15 hours. Researchers say that this warming period, although brief, plays a role in the brain’s survival. Moreover, during hibernation the arctic ground squirrel’s head seems to remain slightly warmer than the rest of its body. During lab experiments, the neck temperatures of the squirrels mentioned above never dropped below 33.3 degrees Fahrenheit (0.7°C).

When the squirrel emerges from hibernation, its brain returns to normal activity within about two hours. In fact, one study suggests that the squirrel’s brain works even better after hibernation! Experts are baffled by this astonishing recovery. They compare it to new growth emerging from scorched earth within days of a forest fire.

Researchers hope that their study of the arctic ground squirrel will help them understand the human brain’s potential more fully. Their goal is to learn more about how to prevent or even reverse the cellular damage that occurs in brain diseases, including Alzheimer’s.

The Lantern of the Photuris Firefly

THE lantern, or light organ, of a particular Photuris firefly is covered with jagged scales that dramatically enhance the brightness of the light that the insect produces. * Jagged scales Consider: Researchers have found that tiny scales on the lantern surface of some fireflies form a corrugated pattern, somewhat like overlapping shingles or tiles. The scales tilt up at one end by just 3 micrometers —less than one twentieth the thickness of a human hair. Yet this tiny tilt lets the lantern shine almost 50 percent more brightly than it would if the scales formed an even surface!

An Overview of Indonesia

Land Straddling the equator between Australia and continental Asia, Indonesia is the world’s largest archipelago. Most of its more than 17,500 islands feature rugged mountains and dense tropical forests. With more than 100 active volcanoes, it is also the most active volcanic region on earth.

PORTRAITS FROM THE PASTIgnaz Semmelweis

IGNAZ SEMMELWEIS may not be a household name, yet his work has benefited most modern families. Born in Buda (now Budapest), Hungary, he received his medical degree at the University of Vienna in 1844. On taking up his post as assistant to a professor at the First Maternity Clinic of Vienna’s General Hospital in 1846, Semmelweis faced an appalling reality —more than 13 percent of the women giving birth there died from a disease called childbed fever. Various theories as to the cause of this disease had been proposed, yet no one had solved the mystery. All attempts to reduce the mortality rate proved futile. Troubled by the spectacle of numerous mothers suffering a slow, agonizing death, Semmelweis determined to find the cause of the disease and prevent it.

Rielyn Co

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