PHOTO: LORNA FAULKES ILLUSTRATIONS: LINDSAY LEIGH“I had an old one die the other day, but by the time I
found him it wasn’t very pleasant as the room is so
warm,” Faulkes recounts. “What is it that packs up first?
Is it their ticker or something else? Nobody really
knows.” He and his team have found no signs of heart
problems or cardiovascular disease in their older
animals. Naked mole rats also seem to avoid the typical
muscle wasting that sets in with old age until their very
late twenties.
To find out why, the researchers are investigating
mole rat mitochondria – the microscopic ‘power
stations’ inside cells. Unlike other cellular structures,
mitochondria have their own DNA that contains a
handful of genes. This DNA tends to pick up damage
over time, eventually causing mitochondria to wind
down in later life.
Faulkes and his team have found that muscle fibres in
older naked mole rats look just as good as those in
younger specimens, and are bursting with young-looking
mitochondria. Furthermore, certain mitochondrial genes
are much more active than those in mice, and there are
many more copies of the mitochondrial DNA. He thinks
this extra DNA dose might be buffering the effects of
genetic damage, keeping mole rat mitochondria
powering on well into old age.GENETIC SECRETS
Dr João Pedro de Magalhães and his team at the
University of Liverpool have also gone in search of theCould one of these other long-lived animals hold
the key to living forever?AS OLD AS
THE HILLS
OCEAN QUAHOG CLAM
Living in the chilly Arctic seas, ocean quahog
clams have such a slow metabolism that they
can live for centuries. One clam, known as
Ming, was thought to be 507 years old when
captured. Ocean quahogs also don’t seem to
age once they’ve reached maturity – this is
known as ‘negligible senescence’.BOWHEAD WHALES
Thought to be the longest-lived mammals,
one male bowhead whale has been estimated
to be 211 years old. Scientists studying the
bowhead genome have discovered
interesting variations in genes involved in
cell growth, DNA repair, ageing and cancer,
hinting at possible reasons for their
longevity.‘IMMORTAL’ JELLYFISH
Officially known as Turritopsis dohrnii, these
jellyfish aren’t strictly long-lived, but they do
have the ability to completely regenerate in
the face of starvation, injury or other stress.
Adult jellyfish can shift all the way back to an
embryonic state, effectively respawning and
starting the game of life again.BRANDT’S BAT
Several species of bat can live for at least 20
years, but the Brandt’s bat holds the record
at 41. Its small size gives it the longest
lifespan in proportion to body size of any
mammal, and its longevity is thought to be
down to mutations in two genes involved in
its hormone system.GIANT TORTOISES
Galapagos and Aldabra giant tortoises are
renowned for their impressive age and slow
lifestyle. One Galapagos tortoise, Harriet,
was reportedly collected by Charles Darwin,
dying more than 150 years later in 2006. An
Aldabra tortoise, Adwaita, was estimated to
have died at 255, which would make him the
oldest terrestrial animal known to science.SCIENCE