Animal Aging Differences
Country: United States
Date: March 2005
Since dogs are mammals with virtually all the same organs
as humans, why do they age so quickly in comparison?
In general, the smaller the mammal, the shorter the life span, for
example rats live only 2-3 years before they die of old age. I've
never heard a good theory to explain this but it might have something
to do with their metabolic rates. The smaller the animal, the higher
the metabolic rate or calories burned per hour per gram of body
weight. One of theories of ageing is that free radicals like atomic
Oxygen or H2O2 (peroxide) cause chemical damage to essential enzymes
and DNA, and the higher the metabolic rate, the more free radicals are
produced per unit time.
Ron Baker, Ph.D.
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Update: June 2012