DOMINIQUE DEMILLE:
Oh, they is coming.
SPEAKER 1: For over
40 years, Joyce Poole
has been studying elephant
populations in Africa.
She's one of the world's
experts on elephant behavior
and communication.
Her work has taken her
to Gorongosa National
Park in Mozambique, where she's
working with local scientists.
DOMINIQUE DEMILLE: Oh, the
big guy is coming out, right?
JOYCE POOLE: He's the same
guy on the camera traps
who was in the farms.
I'm studying the status of
the Gorongosa elephants,
looking at how they
have and are recovering
from a period of heavy poaching.
SPEAKER 1: Many of the
large mammals, and over 90%
of Gorongosa's elephants were
killed during a civil war
that lasted from 1977 to 1992.
JOYCE POOLE: So even
though it's 20 years,
we can see that there's real
scars on this population.
DOMINIQUE DEMILLE:
[SPEAKING PORTUGUESE]
SPEAKER 1: The
scientists are monitoring
a peculiar characteristic,
one that they've also
seen in other African parks.
Some elephant populations seem
to be missing their tusks.
Since 2008, the Gorongosa
Restoration Project
has been protecting
wildlife in the park
and monitoring their recovery.
The elephant
population is slowly
growing back to a healthy size.
DOMINIQUE DEMILLE:
[SPEAKING PORTUGUESE]
SPEAKER 1: By
studying the recovery
of Gorongosa's
elephants, Poole observed
that many females lacked tusks.
JOYCE POOLE: The first
day I was here in 2011,
I met a group of 50 elephants.
Most of them were tuskless.
So I knew straight
away when I came here
that there was a high
proportion of tusklessness.
SPEAKER 1: Tusks are a pair of
elongated teeth, the incisors,
that continue to grow throughout
an elephant's lifetime.
Elephants use their tusks
to strip bark off trees
and dig holes for
water and minerals.
Males use them in contests
against other males
to win over females.
JOYCE POOLE: Elephants use
their tusks all the time.
For males, tusks are really
important because males
are fighting one another
for access to females.
And if you don't have tusks,
you risk being severely wounded.
So there's a very strong
selective pressure
among males for tusks.
SPEAKER 1: Because tusks are
so critical to the survival
of males, tuskless males
are extremely rare.
But a proportion
of female elephants
are typically tuskless.
In populations less
affected by poaching,
tuskless females are only 2%
to 6% of the total number.
JOYCE POOLE: Tusklessness,
just like having tusks,
is a natural trait.
And it's inherited, like
bigger ears or smaller ears,
or green eyes or blue eyes.
It's an inherited
characteristic.
SPEAKER 1: During the
Civil War in Mozambique,
large-tusked
elephants in Gorongosa
were killed for their
ivory, which was sold
to buy arms and ammunition.
More of the tuskless
female elephants survived.
JOYCE POOLE: Here in Gorongosa,
among the older age class,
that is, the ones who
were already adults
during the war, when
there was heavy poaching,
they are 50% tuskless.
SPEAKER 1: Poaching selected
for tuskless females.
JOYCE POOLE: It ends up
with a higher proportion
of tuskless animals, who
then reproduce, and tend
to produce tuskless offspring.
SPEAKER 1: Surveys conducted
by Poole and colleagues
indicated that 33% of females
10 to 20 years old are tuskless.
No tuskless males
have been found.
JOYCE POOLE: Any
animal who's under 20
was born after the war.
So they are not a
consequence of poaching,
or at least not
directly, but they
would be a consequence of maybe
being born of tuskless mothers.
SPEAKER 1: Poole has observed
large tuskless populations
in other African countries where
elephants are heavily poached
to support the ivory trade.
JOYCE POOLE: Somewhere like the
Selous in southern Tanzania,
Queen Elizabeth.
Both of those populations
went through heavy poaching
in the '80s, and
Selous, again, now.
And they have also very
high levels of tusklessness.
In this day and age now,
with all the poaching
that's going on, actually,
the tuskless elephants
are at an advantage
because they are not
being targeted for their tusks.
SPEAKER 1: The insatiable
demand for ivory
is driving complex changes
in elephant populations.
Not only are elephant
numbers decreasing across
the African continent due to
habitat loss and poaching,
but elephant traits
are also changing
as a result of this
ongoing threat.
