Carnivorous plants.
Ingenious killers in beautiful alien form
with exquisite traps ready to ensnare unsuspecting insects.
These meat eaters are mostly small.
But on remote mountains in Southeast Asia, giants are growing
and they're desperate for much larger prey
like warm-blooded mammals.
So why on earth would a bat voluntarily lie down to rest in a carnivorous plant?
Where did they come from?
Why are they here?
The rise of the carnivorous plants began between 60 and 125 million years ago.
In the age of the dinosaurs,
this murderous form of flowering plant began to evolve in places
where the soil was poor or non-existent.
Across this ancient world,
desperately hungry plants that were unable to get nutrients from the soil
converged independently on the same solution.
Eat meat.
They didn't have to look far for their prey.
Insects, they're constant companions, gave them all they needed.
But transforming into a meat eater with no means of stalking prey
requires mechanisms to lure, trap and digest food.
Carnivorous plants worked with what nature gave all flowering plants,
nectar and leaves.
Normal plants use nectar to attract pollinators.
Carnivorous plants use it to lure insects to their death.
Some even disguised themselves as flowers.
Others don't bother to hide their true nature
with striking appendages smothered in nectar.
Insects looking for sweet rewards
will find themselves on a slippery slide to oblivion.
Normal plants have leaves to harness sunlight for photosynthesis,
but carnivorous plants have transformed them into ingenious traps
with failsafe control mechanisms.
But what to do with all that meat?
Carnivorous plants secrete digestive juices just like we humans do.
Enzymes and acids break down their prey.
But all these clever adaptations come at a cost.
To lure, trap and consume their prey,
carnivorous plants need to use a lot of energy.
And there's another problem.
Their modified leaves are no longer the right shape
to extract enough energy from sunlight.
This means that many of them are doomed to be small and slow growers.
But there's one group that defies the rules.
Nepenthes, the tropical pitcher plants.
These are the giants of the carnivorous plant world.
Some of them are big enough to trap small mammals.
High on the slopes of Mount Kinabalu in Borneo,
you'll find the world's largest carnivorous plant.
It didn't grow this big on insects, which certainly aren't plentiful up here.
So what does it eat?
The mystery has only recently been solved.
This is a mountain tree shrew.
The Rajah pitcher plant holds enough digestive fluid to drown and eat the shrew.
But the plant doesn't want flesh.
It's lured the shrew here with nectar
that oozes from a large lid hanging above the pitcher.
To get to the nectar, the shrew has to sit over the pit trap.
It's a perfect fit and not even slippery.
So the visitor won't fall in.
But its scat will.
Between 57 and 100% of the nutrients the Rajah pitcher plant needs to survive
come from feces.
The Rajah pitcher plant's latrine and feeding station
are open for business 24/7.
After dark, the summit rat comes to eat
and also leaves its skat.
But the latrine hasn't been designed to fit all sized behind's.
Small rats like this one can easily fall into the pit trap.
Could the plant have evolved to be a rat catcher as well as a waste collector?
The remains of rats have been found in several Rajar pitcher plants,
but scientists suspect that the deaths were accidental.
In 2009, another strange relationship was discovered...
Between Nepenthes hemsleyana and a tiny flying mammal:
Hardwicke’s woolly bat.
After a long night of foraging, the bat seeks out the pitcher plant.
It's not after nectar.
It's after a place to roost.
The plant has evolved to have a dish shaped wall at the back of the pitcher,
which reflects the bat's echolocation calls,
so it can be distinguished from other plants.
The pitcher is just the right shape to fit a little bat inside.
A fit so snug there's no chance that the bat will slip further down.
It's the only bat species that has ever been found roosting in pitcher plants.
The pit provides
a climate controlled and vermin free home for the bat
and rent is paid in poop.
Nepenthes hemsleyana needs this fertilizer more than most.
It's really bad at catching insects, produces no nectar
and has very little digestive juices.
And that's very lucky for this bat.
Unlike most animals dealing with carnivorous plants,
it's free to come and go without the risk of being eaten alive.
Has the idea of flesh eating plants captured your imagination?
Well, there's more to come about a particularly greedy kind
whose mouth can never be full enough.
So, stay tuned and subscribe to be sure you don't miss out.