NARRATOR: There are far deadlier creatures

lurking in the undergrowth, as I discovered when

I was out looking for firewood.

This tree right here is a perfect one.

See this bark?

It's like paper, and it just peels off just like that.

The bark of this birch tree is waterproof and flammable,

which means it'll burn, even in the rain.

[suspenseful music playing]

Whoa.

Look at that.

[suspenseful music playing]

I did not even see that there.

[suspenseful music playing]

Look at the colors on it, and look

at how it matches this lichen.

It's so well camouflaged.

But this beautiful snake is also a deadly one.

[suspenseful music playing]

They have infrared sensing pits.

It's a kind of sense that humans don't have, but pit vipers do.

This stealth predator can detect its prey even

in complete darkness, and it's armed to the teeth.

Look at those things right there.

They have hinging, venomous, hypodermic needles.

And those hypodermic needles, those fangs,

are hooked up to venom sacs in the back of its head.

And that venom is likely to be some of the most powerful

in the world.

I need to be incredibly cautious.

This snake is certainly capable of delivering

an extremely venomous bite, one that could even kill me.

It's kind of twisting up here.

I'm starting to push my luck, so I'm going to release

it carefully and retreat.

[suspenseful music playing]