Does Aging Always Increase Risk of Death?

For most mammals, aging increases our probability of dying -- it seems like a given. Learn about one animal, the naked mole rat, for which age has no impact on mortality in this episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff production of iHeart Radio. Hey, brain Stuff,
Lauren vog obamb here, how would you like to live
five times longer than a mammal your size has any
right to expect? It sounds great? Right? But wait? Would
you still be interested if it meant you had to
live out your days looking like a tiny alien dressed
in an old sock made from the skin of somebody's

(00:23):
hard living grandpa. Take a minute to think it over.
Naked mole rats taxonomic name Heterocephalus glaber have made their
evolutionary choice in this regard. This cold blooded rodent is
incredibly long lived. They routinely lived the ripe age of
thirty five. Compare that to porcupines and guinea pigs, close relatives,
which usually live no longer than age eight. Naked mole

(00:45):
rats very rarely get cancer, are nearly incapable of feeling pain,
and when the oxygen runs out in their underground tunnels,
they basically start acting like plants. Their bodies automatically switched
from using oxygen to process glucose into energy in their
cells to process reserved stores of fructose into energy like
a plant. Wood no oxygen necessary, and in a study

(01:06):
published in eighteen based on analysis of the life histories
of thousands of naked mole rats, researchers found that while
the rodents not only live incredibly long lives, they also
don't really age seriously. Their risk of dying just doesn't
really seem to increase as they get older, and female
fertility doesn't seem to decline with age either. The term
for this is negligible. Sentizens and lobsters and glapcost tortoises

(01:30):
are two other examples of animals with these qualities. Study
author Rochelle Buffenstein, a comparative biologist who works for the
longevity focused California biotech company Calico, has studied naked mole
rats for more than three decades and has recorded the
life history of each of the three thousand, three hundred
and twenty nine animals that have passed through her lab
in that time. What she's found is that naked mole

(01:52):
rats are a huge exception to the slightly unsettling Gumpert's
Law of mortality, which was developed in eighteen twenty five
by British mathematician and insurance actuary Benjamin Bomparts to assign
a mathematical formula to the phenomenon of aging. Actuaries calculate
the financial risk and insurance company assumes by ensuring a
given person. For humans, the Gomperts law states that after

(02:15):
the age of thirty, the likelihood that we're going to
die doubles every eight years. Some variation of this law
applies to basically every other mammal we know about, with
the exception of Buffenstein's lab reared mole rats. Once Buffenstein's
naked mole rats reached sexual maturity at about six months
of age, she found the likelihood that they would croak

(02:36):
reached around one in ten thousand, where it hovered for
the rest of their lives. Since only a few of
Buffenstein's naked mole rats were not killed in experiments or
moved to other labs, we don't actually know how or
if the naked mole rats strong longevity game eventually hits
a wall. The oldest individual in the study is currently
thirty five years old, so who knows. Aging could happen

(02:58):
really quickly for these superheroes after a certain point in time,
But for the rest of the over thirty mammal crowd
out there try to have a just okay day to
day in spite of the fact that the likelihood of
your death is roughly doubling by the decade. Today's episode
was written by Jesslin Shields and produced by Tyler Clang.

(03:20):
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