Well, as New Zealand has no indigenous territorial mammals and is a remote island, there was no need for the Weta or birds such as the Kiwi to fly away from ground-based predators.
Not a fan of insects? There's one creepy crawly that's sure to make your hairs stand on end - as it's as big as a gerbil. You would not want to wake up with one of these on your pillow!
The Giant Weta is a flightless member of the cricket family, but don't panic just yet - it only lives in New Zealand.
It's the heaviest insect in the world. Not counting antennae and limbs, the Giant Weta can grow up to 10cm and weigh in at 35g.
The largest species of giant weta is the Little Barrier Island giant weta, also known as the Wetapunga. One example reported in 2011 weighed 71g - heavier than a sparrow.
The smaller Tree Weta, sill huge for an insect, is known to use its pincers to dismember rival males when fighting for the attention of a female.
Why so big?
How did this massive bug come into existence and why can it not fly?
The size of the Giant Weta is a result of the greater amount of oxygen available 300-400 million years ago as opposed to now.
Insects breath through holes in their exoskeleton which limits their growth, but with prehistoric oxygen levels the Weta was able to evolve to its current gigantic size.