With nightfall, the competition
in the jungle intensifies
as many of Bornio's 180 species of frog
now burst into song,
all singing for a mate.
The bigger the frog,
the louder the call.
But this male treehole frog is barely bigger
than a fingernail.
He'll need to do something special if he wants to be heard
by a nearby female.
She may only be meters away, but
the chorus from the other frogs is deafening.
This tiny male, however, has a trick
where he searches for a tree hole.
The size and shape of the hole,
are critical.
He then does something remarkable.
It begins with a sound check.
Too low.
It changes pitch.
Too high.
That's it.
At this specific frequency.
The tree hole resonates, amplifying the sound
and broadcasting the call.
More than 50 meters across the forest.
For a female, it's music to her ears
With superb directional hearing.
She can home in his calls
Finally the tiny couple meet.
Hidden from predators.
The tree hole will go on to make an ideal nursery
for their tadpoles.