We're in the Pacific...
...about 1,000 kilometres west of South America on the equator.
Martin Wikelski is heading or his research site.
It's an island called Santa Fe, part of the Galápagos Archipelago.
Santa Fe, like all the Galápagos islands,
is the tip of a volcano that became land
only a few million years ago.
Many of the animals and plants that now live there
are found nowhere else on Earth.
These island species have long fascinated biologists
interested in evolution.
But this is also a good place for animal physiologists to study.
Like all animals found in isolated, oceanic island groups,
the species found in Galápagos are astonishingly unafraid of people...
...because of the absence of predators.
And even on an inhabited island, on a hotel patio,
marine iguanas, a Galápagos species, lounge in the shade of the chairs.
With few natural predators, they don't see people as a threat.
They're easy to observe and study.
And a source of fascination.
Martin's work is on the marine iguana.
He's going to Santa Fe because it's home
to more than 10% of the world's population of these animals.
And here they're undisturbed by humans.
If you study animals here,
you're as close to understanding them as you can get.
This is the nitty-gritty of research.
What we can read in textbooks is knowledge,
one from situations like this.
There's actually an easier way onto the island.
There's a beach but it's four kilometres away
and that would mean carrying all the equipment to the research site.
So the researchers prefer the quick route.
Most of the islands in the Galápagos Archipelago are uninhabited.
In fact, you need permission to land on them.
Everywhere the human species goes, it affects the environment.
This is one of the few remaining places on the planet
where human influence and access is being tightly controlled.
It took Martin months to secure permission to work here.
More people have been up Mount Everest
than been allowed to come to this place.
This will be the group's laboratory, eating and sleeping quarters.
Everything needed for the three months' stay on the island
has to be brought with them.
It's a condition of their permission
that everything is taken away at the end.
So now they're here, what are they going to do?
First, catch your animal.
The iguanas don't fear him but are slightly wary,
staying beyond arm's length.
Again, this remarkable lack of fear of humans.
It doesn't like being handled but it is astonishingly passive.
The basic data first.
Body temperature, obtained by putting a thermometer
into the cloaca pouch,
which all reptile species, males and females, have.
It's 30.0.
For a cold-blooded animal, the temperature may seem high.
...
But it has spent most of the day soaking up the sun.
Next, length and weight.
These are basic pieces of information
but are crucial in understanding how this creature lives.
That's 2kg and 100g.
And for the next three months, this animal is one of the sample
that are going to be intensively scrutinised.
So it needs to be picked out from the crowd on the rocks.
Each animal is given a distinctive mark and a number.
The range of species found here, and here alone,
makes these islands an endless source of fascination for biologists.
Santa Cruz, the main inhabited in the archipelago,
is home to most of the scientific work.
At the Charles Darwin Research Station,
a study is underway, which relies as much on the geographical position
of the Galápagos, on the equator, as the species itself.
The giant tortoise.
Beatrix Schramm collects environmental information.
First thing every morning, she measures temperature, humidity
and takes a reading of light intensity.
She's interested in the mating behaviour of the tortoises
and is trying to find out what triggers it.
As the Galápagos are on the equator,
the length of day doesn't change all year round.
So what is triggering the mating behaviour?
Beatrix is looking for measurable signs of sexual activity.
For the physiologist, the starting point is sex hormones,
which can be found in the urine.
Collecting urine from a 70kg tortoise is a bit of a problem.
So she gets them from the next best thing.
Fresh faeces.
This faecal samples... I'm not sure from where.
This other one, there are two, I am not sure from whom
because, as you see, there are tortoises just running away now.
Because they are so fast, it could be from another one.
I don't know who else stayed here.
So this will be a little bit older. It's not so humid any more.
This one, perhaps, a little older. Like one hour or something like that.
You can check this. If there is lots of humidity, they just did it.
That's why I have to run.
If I see a tortoise and she's sitting somewhere
and she sees me, she runs.
I have to run, too, to look from which direction she was coming
and when I see she's running away from this faecal sample,
which I can see now -
she's half a metre away, I know this is from her.
But the best way is always that you can see the animals sitting
exactly on top of the faecal sample.
You can see where the tail is,
there is some faeces and you can collect it.
That's the best.
The animals produce the faeces first thing in the morning
and she needs it fresh.
They know she's around so it's a bit of a game of hide and seek.
Even when the animals are secure, in a rock-walled compound,
finding them can be tricky.
Tortoises can be extremely quick and are very shy.
To use a sample of faeces in her research,
she has to be absolutely sure
that it has come from the tortoise she has spotted.
There is one.
And the sample really must be fresh.
Any delay and the hormones in the faeces
are degraded very quickly in the heat.
I know exactly where she's sitting.
So if she runs away when we're coming,
I know that this is the faeces of her.
And now.... A very fresh one.
I have to collect that.
Success.
The next job is to stabilise it before any changes take place.
In a nearby lab, she teases out a 4g sample of the material
and suspends it in alcohol.
The sample is now ready for analysis.
But although the station has sophisticated facilities,
compared to Martin Wikelski's iguana research setup on Santa Fe,
we're still over 1,000 kilometres away from the nearest equipment
capable of analysing for the testosterone and oestrogen
at the extremely low concentrations found in faecal samples.
So the samples are chilled. and stored for later analysis.
The telltale signs of the volcanic origins of Santa Fe
are littered all around.
For most of the year, the island is parched, desert-like.
Three months can seem a long time in this sort of environment.
It's the sort of research you need to pace yourself for.
The marine iguana is something of a curiosity.
It's the only iguana in the world that lives by and in the sea
and it's only found on the Galápagos Archipelago.
Iguanas probably arrived on these remote islands
on rafts of vegetation and adapted to the local conditions.
Some, like the land iguana on Santa Fe,
adapted to eating the cactus pads.
The marine iguana has adapted to eating the seaweed
on the rocks close to the shore.
But foraging for this food has caused them a number of problems.
As they are cold-blooded and the sea is cold,
they must warm up in the sun before going down to the sea
to graze on the algae.
The chilling effect of the sea means that they must rest up for the day,
warming up again.
Passively digesting their food...
...with the males indulging in occasional territorial skirmishing
or having ticks picked off them by a ground finch.
Until the next foraging excursion.
The chilling effect of the sea is apparent
in the effort they have to make to get back onto the land.
After a long excursion,
holding onto the rough lava blocks and climbing to safety
is visibly draining.
But how draining?
What is the measurable impact on the animal?
With a simple strain gauge, the animal is pulled off the rock.
Correlate this against its weight and body temperature,
at the time of the experiment,
and you have an index of stamina.
That's five kilos exactly.
But there's one problem with this experiment.
If all the iguanas he can catch are hot from basking in the sun,
how can he measure one as if it's just come out of the sea?
Improvise.
A nearby tidal pool, used as a playground by sea lions.
It's a convenient place to bring an iguana down to low temperature.
But you have to shift the residents for a while.
Another index is speed.
Time trials for iguanas.
They take significantly longer periods to run the course
when they're colder.
It's as good an index a performance as you need.
What's more, the experiment is conducted so close
to where the animals live.
The disruption to their lives -
always a problem in experiments on animals -
is minimised.
I will put it here if you can help us there.
OK.
Beatrix needs a check on whether the sex hormones
collected from the faeces are a reliable indicator.
She periodically takes a blood sample from her tortoises.
This week, it is the turn of a large male called Chico.
A procedure which I'm lucky enough to help with.
Sometimes we have to change the arm because it's the same with us -
some veins are good on one side, some are very bad.
So we try the other side.
So you can see, here, this part and these lines
going from there till this tendon.
Here is a tendon from the muscle.
And we are following this line, going in this small hole.
Here's the vein going up there and so we try to find this vein.
You can't just feel it so you have to follow these lines.
That's the best.
Sometimes it's difficult to find it. Sometimes not at all.
I got it. You see?
When you've got it, it's just a few seconds.
Then you have it.
Muchas gracias, Chico!
Now we have to be very fast.
This is a heparin tube.
Thank you very much.
So this is a heparin tube and afterwards I will centrifuge it.
I will centrifuge it for about five to ten minutes.
We only need the blood plasma inside
so we will throw the blood cells away.
In the blood plasma, there are the sexual hormones.
These we need.
At very low spring tides,
when rocks which are normally covered or exposed,
the iguanas graze the red algae.
Martin takes a chance to sample the weed
with a watchful eye on the waves.
The samples are analysed to identify the species.
Each has a particular energy content and the growth rate of each is known.
If you know what's in the animal's stomach,
you get a picture of the energy balance,
what and how much it has eaten.
To an expert, the chewed fragments from the stomach are identifiable.
The purple colouration comes from the seaweed itself.
For a complete picture, fresh faeces are collected from the rocks,
dried and analysed for energy content.
Altogether, the researchers
have a snapshot of the energy balance of the animal over a day -
what it eats, how much it eats, what it loses
and, as a result, how much energy
the iguana has extracted from its food.
And now...
OK.
It's ultrasound.
The same technique to look at human babies in mothers' wombs.
The state of development of the early stages of the eggs, the follicles,
is a clear indication of where the animals are
in their annual sexual cycle.
Now you can see this end. You don't see this side so good.
But, nevertheless, you can imagine that this is the growing follicle.
As they approach the time of readiness to mate,
the follicles show up as healthy, viable.
If they are not fertilised, they may be reabsorbed.
Beatrix can see the differences between them.
The ones that are breaking down, known as atretic follicles,
have characteristic hollow-looking features.
Normally you can see a very black hole inside here.
so you just see some different colours like blackish, greyish.
A normal follicle is totally white.
An atretic follicle has some different colours inside.
The Galápagos can seem like a last frontier.
The difficult and sometimes primitive conditions in the islands
can suggest a lack of sophistication in scientific research.
But making devices like the ultrasound recorder,
working in these circumstances,
is nothing less than a research tour de force.
For Martin and his group,
their efforts lie in turning their shelter into a laboratory
where they can undertake the precise and meticulously detailed work
of inserting radio transmitters under the skin of selected iguanas.
Why go to all this trouble?
If your only means of keeping track of the iguana is by looking at them,
you won't know what they're up to when they're out of sight
or when they go into the sea.
What's more, if you're trying to correlate the animal's activities
with the information on food intake and body temperature,
you need some quantitative measurement, some data.
You need a monitoring device that travels with,
or in this case in the animal as it goes about its daily cycle.
Once in place, the transmitter sends back signals to the researchers
as a series of bleeps.
These are counted off against the clock.
After a few calculations, the researchers have a measure
of the animal's body temperature throughout the day.
They can start to piece together a little of its life.
You see here a file of time against body temperature
and you see immediately with the telemetry
we get some nice data sets on certain aspects and certain time periods.
But you see, just between, say,
about 20 hours and in the morning at six hours,
we can't continuously record the body temperature.
We just have to assume that there is a continuous line
of dropping body temperature.
We have some nice information here
on the time that the animal was foraging
and that's a nice aspect of the telemetry.
We immediately get the data on the body temperature
and we can design experiments
to change aspects of the body temperature.
As the graph shows, there are gaps.
The technique is flawed.
The radio signal is quite weak.
If the animal goes behind rocks, the signal is blocked.
You only get information while the researchers are around.
Martin has started to use an new invention.
A device that measures heart rate and body temperature once a minute
and stores it on a microchip, sealed within the implant.
The whole device is sealed in a waterproof resin
and inserted under the skin of an anaesthetised iguana.
There it will stay for several weeks.
After the iguana has had a few days to recover from the operation,
it is released and the data collected.
Later, it will be recaptured and the device recovered.
Then the information can be analysed.
You can see that even though the temperature drops down in the night,
there are some changes.
This is probably because the animal moved its position inside the rocks.
You see a really smooth warm-up curve.
So we can calculate, mathematical function,
on this warm-up curve.
There are no inaccuracies in the data because people didn't count right
or took the time wrong.
You also see during the foraging period,
there's a really nice drop
and afterwards an increase in the body temperature again.
Then also the nice drop in body temperature
in the evening or in the afternoon,
and a little bit of increase when the animal moved from its rock
to a rock that was slightly further in the sun.
That's what they do around four o'clock or so in the afternoon.
So all this can be nicely picked up and interpreted into this file,
if we combine it with our behavioural observations.
Among other things, science is about taking your chances
when you find them.
Martin has always been interested in the diving physiology of the iguana.
If he understands how the heart operates,
he's got a clue about the efficiency of blood flow.
Quite by chance, he finds out about Beatrix's ultrasound work
on the main island.
He jumps at this chance to look at the dynamic of a heart operating.
It's another piece of the scientific jigsaw in place for nothing.
So you can see the heart pumping here.
Now we can make it a little bit bigger.
You see the movement?
And here... It's the largest one, yes.
And here's it's ending. And here, too.
If you move the head of the ultrasound a little bit,
you can see how the blood is going through,
the rhythm of the heart here.
What we've seen here is a snapshot of research taking place,
questions being asked, puzzled over,
and experiments set up to provide answers.
Some of the answers are already there
but, for the most part, it's a long continuing process,
slowly assembling pieces of information,
which as a body of knowledge
informs our understanding of the natural world.
And, perhaps, more importantly,
allows us to conserve and manage this fragile fragment of the planet.