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  • Dec 29, 2014
  • Updated: 10:34am
LifestyleTechnology
BIOLOGY

Tiny bat defies the rule about longevity

PUBLISHED : Sunday, 25 August, 2013, 12:00am
UPDATED : Sunday, 25 August, 2013, 4:58am

From the elephant to the mayfly, biologists have always said there is a general rule about longevity: the bigger the animal, the longer it lives.

But an intriguing exception is the Brandt's bat, a native of temperate areas of Europe and Asia.

The insect-munching mammal tips the scales at five to eight grams - less than two teaspoons of sugar - yet can live for more than 40 years, as long as a dolphin and more than a horse or a cow.

Eager to learn why, an international group of scientists sequenced the bat's genetic code, highlighting a network of genes that could explain its exceptional lifespan.

The study, published in the journal Nature Communications, pinpointed genetic variants that, as expected, give the tiny creature its ability to navigate by sonar and to sense dim and ultraviolet light.

But they also came across "unique" variants that control cell sensitivity to two growth hormones.

One mutation is linked in humans to a form of dwarfism and may be protective against diabetes and cancer, previous work has shown.

"Together with adaptations such as hibernation and a low reproductive rate, [the variants] contribute to the exceptional lifespan of the Brandt's bat," the scientists suggest.

The Brandt's bat takes a long time to reach sexual maturity and produces a single pup at a time, which weighs about a seventh of the parent's body mass.

Meanwhile, another team, based in Singapore, believes other species of bat may help unlock the secret of longevity.

"The most outstanding difference we've seen between bats and other mammals has to do with DNA repair," said Wang Linfa, 53, director of the emerging infectious disease programme at the Duke-NUS graduate medical school in Singapore.

"If the science is as true as we think it is, we can unlock the mechanisms and it can have a huge, huge impact."

Wang's team works on the black flying fox, which is a big bat.

How some species can live three times longer than other mammals their size may be linked to their ability to carry viruses that are deadly to other animals, as well as their low rates of cancer, he said.

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thomas.samaras.77
I have researched smaller human body size and longevity for about 40 years. Some facts that support the bat findings include:
1. Within a species, the smaller individual lives longer: dogs, mice, rats, cows, horses and elephants
2. Smaller women live longer than men (I found that American males are 9% taller and have a 9% shorter life expectancy.)
3. A Spanish study of 1.3 million men found that shorter men live longer.
4. An Ohio study of deceased men and women found that men and women who were shorter lived longer.
5. Data from baseball, football and basketball players showed that shorter athletes lived longer.
6. A study of men in a small village in Sardinia found shorter men lived longer.
7. A study found shorter Japanese Hawaiians lived longer.
8. Centenarians are generally quite short even accounting for shrinkage. I have found no peer-reviewed studies that found tall people represent a majority of the study group.
9. Many studies have found that taller people have a modestly higher death rate from cancer.
10. Many biological factors support the greater longevity of shorter, proportionately lower weight people: lower growth factors, lower glucose, lower blood pressure, lower C-reactive protein, lower Apo B, and lower insulin.
11. Giovannelli found that shorter people had much lower DNA damage.
This does not mean that tall people will die young. As when we compare men and women, many men outlive women although most men die younger.

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