geoff: Globally, one in five
reptile species is facing the
threat of extinction.
That's according to a recent
study in the scientific journal
"Nature."
We take a deeper look now at
what's driving this extinction
crisis and what it could mean
for the rest of the world.
Matthew: This is onyx, a two
year old male komodo dragon.
Geoff: On a recent day at
smithsonian's national zoo in
Washington, we met onyx, a
juvenile komodo dragon.
They are the world's largest
lizard, often growing up to 10
feet long, with some weighing
more than 300 pounds.
Native to a few islands in
Indonesia, these incredible
reptiles date back one million
years.
But because of habitat loss,
komodo dragons are now facing an
uncertain future, says Matthew
Evans, an assistant curator at
the smithsonian's reptile
discovery center.
Matthew: Komodo dragons are --
they are endangered.
And these guys are part of a
species survival plan.
Geoff: That plan is part of a
larger effort here at the
national zoo to highlight why
reptiles are vital to our entire
ecosystem.
Matthew: Komodo dragons are that
what we call a kind of a
keystone species.
So if you remove them as a top
predator in the environment, the
rest of that ecosystem doesn't
function, right?
They actually need that top
predator for all the roles that
it plays with creating habitat
, for keeping population
densities down allows other
, species to breed and flourish
while if they disappear, it is a
domino effect that affects
everything.
Geoff: The plight of the komodo
dragon is not unique, says
zoologist Bruce young, who
recently co-authored the largest
global reptile study of its
kind.
Bruce: Our goal was to assess
every single species known at
We worked with over 900
scientists from around the world
that did know these species.
Geoff: Young says the research
took 17 years to complete and
found that at least 21 percent
of the world's reptiles, more
than 1800 species in all, face
extinction.
Why are so many reptiles in
danger of extinction?
Bruce: There's a few reasons why
most reptiles that are
endangered are, in fact,
endangered.
Loss of habitat, especially
forest habitat from logging.
Also, the expansion of the
agricultural frontier has caused
many habitats for reptiles to
become destroyed and they have
nowhere left to live.
Geoff: The study also found that
if all threatened reptiles were
to disappear, the world would
lose a combined 15 billion years
of evolutionary history.
Bruce: It'll take a big
contribution by governments to
to kind of change the trajectory
we're on.
Geoff: One of the reptiles most
at risk -- turtles, with nearly
60 percent of the species facing
extinction and in need of
targeted conservation efforts.
Scott: We are surveying both the
land and the stream, hoping to
find some turtles.
Geoff: Scott Smith is a wildlife
ecologist for the Maryland
department of natural resources.
He's been studying these
slow-moving reptiles for 30
years.
Scott: Okay everybody ready.
Geoff: We tagged along as he and
a team of scientists surveyed
wood turtles in western
Maryland.
Scott: Wood turtles' main
threats are habitat loss, road
kill, road mortality, collecting
for the pet trade, climate
change.
And we would not know that basic
stuff without having come out
and done these surveys.
>> 71 for shell height.
Geoff: These scientists mark and
measure each turtle they find.
Scott: One problem we're having
here is with reproduction.
We have not found any youngsters
at all.
Geoff: And Smith says nearly all
of the turtles they are finding
are females.
>> It's a female.
Scott: What do you got there?
>> Another female.
Scott: We're seeing skewed sex
ratios towards females because
of higher incubation
temperatures due to climate
change.
And of course, in nature, you
want a 50/50 sex ratio.
Geoff: Another major issue --
human development in areas
turtles have long called home,
leading to an increase in
predators, like racoons.
Scott: There's a lot more in the
landscape now than there were
historically, because they can
feed off our garbage.
They can feed off cat food, dog
food we leave out.
And so we have these absurdly
elevated populations of
predators which feed on turtle
nests.
Geoff: And while these reptiles
face a host of threats, Smith
says turtles around the globe
are faring even worse.
Scott: Certain species are
really on their last legs before
they go extinct.
So we certainly have a lot of
problems, but comparatively to
most of the rest of the world,
our turtle populations are doing
relatively well.
Noah: Turtles actually survived
the meteor that killed the
dinosaurs.
And so, you know, they survived
a giant asteroid hitting the
planet, but they might not
survive us.
Geoff: Noah Greenwald is the
endangered species director at
the center for biological
diversity.
Noah: Many reptiles control
small mammal populations that
control insects, which then has
has impacts elsewhere in the
ecosystem.
You know, those insects then
don't eat plants and don't
otherwise affect things.
One of the concerns about losing
biodiversity is that, you know,
nearly all of our medicines, all
of our foods come from species.
So as we lose these species, you
know, we potentially lose a cure
to cancer.
Geoff: So what's the solution
then to the extinction crisis?
Noah: A lot of the solution to
the extinction crisis is
actually also a solution to
climate change, that these these
two problems are quite
interrelated.
And in particular, we just have
to protect more of the natural
world so species have space to
live.
Geoff: While threats to reptiles
have become increasingly urgent,
wildlife ecologist Scott Smith
says there's still time to act.
Scott: It's not all bad news,
and we as humans can certainly
change our behaviors and act to
reverse this trend.
But we have to do it now.