Absurd Creatures | Meet the Weta, an Insect as Big as a Gerbil

(cheerful instrumental music)

Oh, look, a nice little cricket kind of thing,

minding its own business,

just doing some insect stuff.

How about a human hand for scale?

There you go.

There's some good perspective.

These are weta,

the name of the heaviest confirmed insects on earth.

Thankfully, they only live in New Zealand.

There's actually several different kinds of weta,

and the largest among them is actually quiet peaceful.

It's about the size of a gerbil,

however big a gerbil is,

but there is one variety among them

that don't take crap from nobody.

This is the tree weta,

specially a tree weta that's gnawing

on my nominee for entomologist of the year.

Only males have these enormous mouth parts

known as mandibles,

which they use to fight for females,

and by fight, I mean disembody their rival's limbs.

Now, relatively speaking,

these weta aren't that big

as far as animals go.

I mean, I still tower over them,

so what's keeping them from growing to our size?

Well, it all has to do with respiration.

They don't have lungs like we do.

Instead, they have holes all over their exoskeletons

that deliver oxygen to their tissues.

As the air makes its way through the animal,

more and more oxygen gets dissolved,

so the tissues at the center might get shortchanged.

Grow too big,

and you might not be able to breathe.

Really, weta have only been able to grow so big

because they gave up flight

since on New Zealand,

they never had mammals to worry about eating them,

but 300 million years ago,

there was much more oxygen in earth's atmosphere,

so insects could afford to grow

to unacceptable sizes.

I'm talking dragonflies the size of seagulls,

so breathe deep, ladies and gentlemen.

Breathe up all that oxygen

so the weta can't get out of hand.

(cheerful instrumental music)