>> Michael Tessler: Our first leech of the trip, first terrestrial leech.
There we go!
When you go out into a forest in Southeast Asia,
it can be very difficult to see mammals.
But there are several ways to find out what mammals are in a given area.
You can go and look for footprints, or hairs.
It's very difficult and time-consuming.
Or you can set up a camera trap,
but probably you want to leave it there for several months, maybe even a year.
Turns out what we're able to do is go in,
go to a forest just for a day, collect leeches off the ground,
collect them off of ourselves,
sequence the DNA from their gut contents,
and use that DNA to figure out what mammals are in an area, very efficiently.
Conservation biologists have already started to use these methods.
But our results will help them determine how many leech species to look at,
and how many individuals of each species to look at,
to maximize the number of mammals they can find in an area.
>> Mark Siddall: The idea at you can get what we call IDNA from leeches
that have fed on mammals
or other rare species in an area that's under conservation threat
is something that has developed in the last five to ten years or so.
And into the bag you go.
We had about three weeks to a month to work in Cambodia.
We went to three basic areas.
One is Preah Vihear which is in the north, and getting up towards the Lao border.
Then we were down in the Cardamom Mountains.
This is the highest elevation that you find in Cambodia
And we find that there's usually a greater diversity when you have an altitudinal gradient.
And then finally, we went to Seima, which is a protected forest,
that has recently had tigers and elephants and so forth, over by the Vietnamese border.
And by doing all of that we hope to capture the greatest diversity across the country.
>> Michael Tessler: First blood on the trip. From Lily. How's your first leech bite?
>> Lily Berniker: Ah, I don't feel it.
>> Michael Tessler: You don't feel it?
>> Lily Berniker: Doing field work and having the opportunity to collect these organisms
in their natural environment
allows us to reconnect with the goals that we have as scientists of conserving diversity
and why we study the things that we do.
And it's also a necessary part of doing this type of research.
When the leeches were present in large numbers, it didn't take long for us to spot them,
and it didn't take long for them to find us.
And so the collecting was actually quite abundant and it was quite successful.
In order for collection data to be useful for our research and for future research,
we really want to as accurately and as detailed as possible
record the location where we collected these animals.
That includes when possible GPS coordinates,
the date when the individual was collected,
or any kind of environmental factors
that would influence the presence of that specimen when it was collected.
If anyone else in the future wants to go back and revisit a location,
in order to find the same species or to understand which mammals were present,
that person can find the location where we were collecting.
>> Michael Tessler: The DNA so far have been pulling out a number of different animals.
We've been finding bats,
we've been finding civets,
we've been finding barking deer,
mouse deer--really tiny deer.
And interestingly, we've started to even find birds,
which are very rarely reported to have leeches actually feeding on them.
>> Mark Siddall: The 2015 Niarchos expedition to Cambodia allows us to do the sorts of things
that we do best as biologists,
and that is not just to know the diversity,
but to see them in context.
When you find this species of leech or that species of leech,
is it in a bamboo forest or is it in a hardwood forest?
Is it at this altitude or that altitude?
Was it a rainy day, was it a sunny day?
And really get the context of discovery associated with
the specimens that are right here in the Museum.
>> Michael Tessler: Leeches are certainly an overlooked organism.
Very few people have studied them.
There's very little known about them.
Even though it's not a huge group with about 700 described species,
there have only been a couple people who have dedicated their profession
to study these organisms
and there's a lot to be discovered on all levels.