Life Nature Magazine

IN THE FIELD FROM DUSK UNTIL DAWN AUTUMN ISSUE
Images: Clare Greenwood, 2013. Illustration: Chris Beirne, 2013.
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Old timers:
Chris Beirne
I’m suddenly startled by a rasping bark
ringing out across the wooded valley,
in the semi-darkness of this warm
summers evening. The call sounds like it
might belong to a large and vicious predator
and if you believed the local tales, you
would know that a ‘big cat’ stalks this area
of forest. Thankfully, my common sense
intervenes. I am not in a wild and isolated
fragment of the Amazonian rainforest but
sat on a fallen beech tree just three and a half
kilometres from the M5 in Woodchester
Park, Gloucestershire, and the vicious
caller is in fact, a roe deer. I am trying to
catch a glimpse of the notorious nocturnal
mammal that is present here in abundance
- the European badger. Badgers live
in large underground networks
of tunnels called setts; in
this location and many
others in the
south of
England, they live communally with other
badgers in social groups. As the barking roe
deer moves away all is quiet and my mind
begins to wander again.
I have been studying badgers for the last
two years in order to understand the aging
process. On the surface of it, that sounds
pretty strange. Why would you study badgers
in order to understand how things age?
First and foremost, humans are far too long
lived to collect data on during the timescale
of a normal PhD (3 to 4 years), so I would
be looking at less than 5% of an individual’s
lifespan. Secondly, most of what we have
learnt about ageing comes from laboratory
strains of rats and mice. Such organisms are
highly inbred to ensure that each individual
is as genetically identical to each other as
possible and they are reared in exactly the
experiments are repeatable. However, it’s
the variation in ageing rates that make it
all, everyone gets old, but why do some
people get old faster than others? Working
on a wild population of mammals - such as
badgers - embraces the variation that might
be important in determining how long an
individual lives and how fast it ages.
Everyone gets old, but why do some people get old faster
than others? Working on a wild population of mammals
- such as badgers - embraces the variation that might be
important in determining how long an individual lives
As badgers have a highly tuned sense of
smell I have positioned myself downwind
from one of the larger setts within the aptly
named ‘Beech social group’. After such a
warm summer, the leaf litter is tinder dry,
so if there are badgers on the move I should
hear them well before I see them. Sure
to hear the rustling of leaves further up the
one badger up there, there’s a whole group
of them! Despite the proximity of the noise,
the darkness leaves me sightless.
The Food and Environment Research
Agency (FERA) have been trapping the
badgers in and around Woodchester Park
for over thirty seven years in order to
understand how bovine tuberculosis (bTB),
a disease particularly damaging to the
cattle farming industry, spreads between
groups of badgers under natural conditions.
given a unique tattoo in order to identify
each individual and on each subsequent
occasion the badger is caught, it is tested
for bTB. I also take a small blood sample
from each badger in order to take back
to the University’s Molecular Genetics
Lab and measure each badgers telomere
length. A telomere is a region of repeating
‘TTAGGG’ nucleotide sequence at the end
of each chromosome which protects the
vital gene coding regions of DNA from
degradation. In humans, and some species
of birds, telomeres are at their longest at
birth then steadily reduce in length as they
are eroded by cell division and the ‘wear
and tear’ of everyday life. Telomere length
is positively associated with the number
of times a cell can divide, the longer they
are the more times a cell can divide in
culture. As such telomere length has been
suggested to act as a molecular clock
which determines your biological age.
However most of the telomere research
conducted to date has been performed on
animals grown in controlled conditions. I
important determinants of longevity
in wild populations under natural
conditions.
Just as I am starting to lose all
hope of spotting a badger, I hear
a rustle to my left. A solitary
badger ambles out of the darkness
and takes me by surprise. It stops
way and that, searching for
earthworms. It is impossible to
tell in the half light but I hope it is
badger “L54” or his brother “L56”
who have been captured every
year here since they were born in
the year 2000. I know for a fact
they both have cataracts, and most
likely arthritis to boot. Before my
makes them live so long. Is it super
long telomeres, good genes, or
have they simply ridden out their
luck for the last thirteen years?
Suddenly the wind shifts and the badger
stops in its tracks. As soon as it catches a
from whence it came.
Chris Beirne uses his
knowledge of molecular
techniques to understand
the proccesses which cause
the individual differences
in ageing rates, working
with the Centre for Ecology
and Conservation at Exeter
Cornwall Campus.