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The Fountain of Youth

What's the secret to longevity? If we look to the animal world for clues, the answer seems to be: stay cool and take longer naps.

A general rule of biology is that larger species tend to live the longest. So it's no surprise that elephants and whales are among the longest living mammals on the planet. But some small species reach old ages, too.

The Little Brown Bat, one of North America's smallest mammals, can live thirty-two years or more. The key is an ability to decrease its body temperature and slow its heart rate significantly while resting. The Little Brown Bat also spends its winters hibernating in caves and other climate-controlled locations.

Some high-altitude ground squirrels adopt a similar strategy. Mature squirrels (which are thought to live twenty or more years) may be active for as little as three months of each year. During fall, winter, and most of spring, these squirrels hibernate underground. The only ones active during early spring, late summer, and fall are juveniles.

Birds follow a similar pattern. Larger species, such as ostriches and condors, are among the longest lived. Hummingbirds, with their extremely small size and high metabolic rate, hardly seem like candidates for our list. Yet these tiny birds have the ability to lower their metabolic rate and basically become dormant at night or when the weather makes feeding impractical.

Current research involving Laysan Albatrosses is showing that these large seabirds also live a long time -- forty-five years or more -- despite lifestyles that seems anything but relaxing. Except during breeding, Laysan Albatrosses spend their entire lives at sea, seldom landing, even to rest on the water. Those specimens breeding in the South Pacific commute several thousand miles to feed in the Bering Sea. The long narrow wings of the birds help them fly incredible distances effortlessly. It should also be noted that these birds often spend the many hours of their trans-oceanic flights asleep.

The most phenomenal tale of longevity, though, concerns the Bowhead Whale, a species that spends its entire life in the cold waters near the Arctic ice cap. Bowheads feed during the summer only and live off stored reserves the rest of the year. Although the species is considered endangered, and therefore off limits to commercial whaling, native peoples of western Alaska are still allowed to take a few each year. While examining carcasses taken during these hunts in 1992 and 1993, several stone harpoon points were found embedded in their flesh. Anthropologists familiar with the tools of Inuit hunters concluded that the points had probably been in the whales since the late 1800s. Subsequent studies of preserved tissues taken from other Bowhead Whales revealed several animals that were probably well over 100 years old and one specimen that was between 177 and 245 years old.

So there you have it. The secret to a long life is to work only when necessary, take the time to do absolutely nothing whenever possible, nap between tasks, don't eat if you don't have to, and stay cool.

 

 

 

 

 

2007 eNature.com