30°C. As a result, they’ve evolved to dispense with the
effort of maintaining the body temperature of around
37°C that’s found in most other placental mammals,
instead conforming to the relatively lower temperature of
the subterranean world around them. “The environment
they live in is what drives a lot of their weird biology,”
explains Faulkes. “They don’t need so much energy
because they’re not thermoregulating, so they can get
away with eating much less.”
There’s a well-established relationship between
having a lower body temperature and a longer life, and
evidence from many species – including fruit flies,
worms and mice – suggests that a low-calorie diet can
significantly extend healthy lifespan. Exactly how this
works isn’t clear. Some researchers suggest that a low-
cal, low-temperature lifestyle reduces the production of
damaging chemicals called free radicals, which are
created as cells make energy. Others think the
explanation is more likely to lie in altered levels of
hormones and other molecules that drive cell growth.
The naked mole rat’s vegetarian diet probably plays a
role too. Their favourite foods are rich in chemicals
known as polyphenols, which are thought to combat
ageing and boost health.
And there are more tricks up the naked mole rat’s wrinkly
sleeve. Many mammals succumb to cancer as they get
older, but mole rat tumours are vanishingly rare, with only a
handful of cases documented in more than a thousand
captive animals. In 2013, scientists discovered that this is
at least partly due to naked mole rats having an unusually
large and sticky version of a molecule called ‘high-
molecular-mass hyaluronan’, which glues cells together.
As well as apparently making their skin super-stretchy
so that they can squeeze through the tightest of tunnels,
the hyaluronan seems to reinforce contacts and
communication between a mole rat’s cells, stopping
them from running out of control and turning cancerous.
Researchers are now investigating the underlying genes
and molecular pathways responsible, to see if we can
use this knowledge to increase human lifespan. Whether
this means we would also end up with the same baggy,
stretchy skin as the naked mole rats remains to be seen.
A MATTER OF LIFE AND DEATH
There’s a further question that needs answering. While we
know that naked mole rats can live for decades, we don’t
really know how they finally die. Infections are rare, barring
the odd tummy bug, and the most common cause of death
is violence. Fights are relatively uncommon, but those
sharp teeth can be lethal. Other than that, it’s a mystery.