Ninety Years at Forty Below
It's not hard to make bad jokes about the situation: a hibernating Siberian animal slept so long he should have been dead, but instead woke up Red. They held the revolution without him.
According to the British journal New Scientist, biologists in the Soviet Union have successfully revived an Asian salamander that had been frozen for 90 years. The researchers, who work at the Magadan Institute of Northern Biology, did not have to rely on advanced technology of any dramatic sort to bring their subject back to life. All they did was put the salamander in a tub of cold water, and the creature's own system did the rest.
How the Soviet scientists established the length of the salamander's sleep wasn't specified, but the behavior of Asian salamanders gives some clues. They select hibernation sites under tree stumps and hummocks of earth, and some will follow cracks and passageways deep into the soil before they settle down to sleep away the cold season. If their chosen crack fills with water that freezes, the salamander can be trapped at the bottom of an ice wedge big enough to stay frozen through the warm months. Some activity disturbing water flow patterns on the surface, such as building a road or cabin, could cause ice wedges to form where none had been before. Thus, a bit of human work that could be marked on the calendar might have led to this salamander's settling in for a record-length winter's nap.
Magadan lies at about the same latitude as Anchorage, but east of the Kamchatka Peninsula, and it gets cold there. The biologists established that hibernating Asian salamanders can survive 40-below temperatures, a record for the amphibian tribe. Most higher animals (and many plants, for that matter) suffer lethal damage at far warmer temperatures, because their cells rupture as the contained water freezes and expands. The salamanders get around this problem by making their own antifreeze--in their livers.
Asian salamanders have the biggest livers in proportion to body size of any vertebrate yet found; it's nearly one-third of their body weight. When the temperature falls, the salamanders' huge livers begin converting their stores of glycogen, an energy-storing carbohydrate, into glycerine, a kind of alcohol. The glycerine spreads throughout a salamander's body and prevents cells from crystallizing. When a hibernating salamander was chilled down to minus 40, the researchers found that crystals of ice did form right under the animal's skin, but its tissues remained elastic and appeared healthy.
Normally, an Asian salamander lives for about ten years. The oversized liver with its great supply of glycogen might help explain why the 90-year salamander survived for so long past its normal span. Of course, it needed almost no energy while it hibernated; unlike a hibernating bear, it did not need to maintain a body temperature warmer than its surroundings. For whatever metabolic processes it did maintain--and there must have been some--that mighty liver held enough fuel.
Possibly it had some to spare. The Soviet scientists believe that even older specimens may yet be found, sleeping at the bottom of ice-filled channels in the earth.
Alaska isn't home to these remarkable salamanders, so we can't go scrounging through ice wedges looking for new record-holders in the animal Rip Van Winkle competition. But think how much more exciting life would be if the mammoth's liver had been bigger!
